Gladion is a young boy with light blonde hair and green eyes. His hair is shaved on the sides with a ripped design carved into it, with long tousled bangs that cover his right eye. He wears a grey hooded shirt with a red slash resembling a scar on it, a black undershirt with ripped sleeves, ripped black pants and, red shoes with grey soles and black laces. He also has a red rectangular bag around his waist. In addition, he wears a Z-Ring on his left wrist.
When Gladion joined with Ash and the group as Ultra Guardians, Gladion's battle suit was different than Ash's group. He wears a black and dark blue battle suit with a navy blue linings in each elbow, and a single red line on the front of his suit to match his red belt. At the back of his belt is gray, black, and dark blue knee-high battle boots. He also had an Ultra Guardian badge at the center of his suit.
Gladion is a serious, calm, and determined Pokémon trainer, who appears to be a reserved loner, but is noted by others to still have kind behavior, as shown when he told his sister, Lillie, to take care of her Pokémon.
Initially, Gladion seems distant from his sister, however, he does deeply care for her. In fact, he swore to protect her after her encounter with an Ultra Beast causing her post-traumatic fear of touching Pokémon. Due to that incident, he has a burning desire to defeat every last Ultra Beast, convinced that they should not exist. When he saw Nebby and Ash's Poipole for the first time, he was distrustful of them, as he believed them to be Ultra Beasts.
Gladion can be impatient, and also has a violent temper, as seen in Mission: Total Recall!, when he harshly scolded Ash for accidentally causing Lillie's traumatic fear of Pokémon to resurface due to his negligence with Nebby.
Over time, he appears to mostly overcome his grudge against Ultra Beasts, and becomes more determined to find his missing father, Mohn, instead. He also becomes more open to others, smiling more often and developing a close relationship with his sister, Lillie.
One day, Mohn thanked Gladion for informing Lusamine his mother that their little baby princess, Lillie, was crying. Gladion was happy for the compliment, while Lusamine and Mohn comforted Lillie, cheering her up. Mohn also lifted Gladion up to see Lillie smiling, to remember the moment as the time they were a united family, with their Pokémon Eevee and Zoroark. Some time later, Gladion and Lusamine entered Mohn's room, where Mohn was experimenting with Magearna. The two were fascinated to see baby Lillie being able to walk, and Mohn mentioined she just learned how to do that. While Lusamine was disappointed not being on time to see how she did that, Gladion and Mohn nevertheless praised baby Lillie. Before Mohn passed away in an incident revolving around an Ultra Wormhole, Gladion's last remaining memory of his father was the latter gently patting him on his head.
Lusamine told a story of the Blinding One, who had created Alola, to her children, Gladion and Lillie. Lillie, Gladion, Lusamine, Eevee and Cleffa used to spend a lot of time together as a family. Gladion was working at the orchard with his family and the Pokémon, and spent a lot of time at the orchard tending the fields. Lusamine kept pictures of her children and their Pokémon in her office. Gladion, as a young boy, watched as his sister, Lillie, was attacked by an Ultra Beast. Lillie was terrified, while Gladion was not brave enough to defend her. Suddenly, a Silvally arrived, which defeated the Ultra Beast. Lillie lost memory of the encounter and became scared of Pokémon, while Gladion took the Silvally as his own Pokémon, and swore to protect his sister.
Gladion was also motivated to go on a journey to find more about himself, as well as to train alone, leaving Lillie and the mansion.
Pokémon the Series: Sun & Moon
Gladion was walking with Umbreon through the streets when he was ambushed by three Team Skull grunts. Gladion ignored them and continued walking, but the grunts demanded he hand over his Umbreon. Gladion eyed them as the grunts sent their Pokémon to attack. Instead, Gladion sent Lycanroc, who used Stone Edge to defeat all three of Team Skull's Pokémon. Gladion continued on and was seen by Team Rocket. He later challenged a sailor, and had his Lycanroc defeat the sailor's Blastoise, impressing the crowd. Ash observed the battle and was told by Rotom that Gladion was a famous trainer on the island. Ash went to Gladion and introduced himself, wanting to challenge him. Gladion ignored him but was called by Lillie, who addressed Gladion as her brother. Gladion was surprised, and when Lillie showed she could touch her Pokémon, Snowy, Gladion simply told how that was great, she should keep it up, and refused to visit the mansion.
He also saw Ash had a Z-Ring and was told by Ash that he got it from Tapu Koko. Seeing how Ash was important, Gladion decided to at least think about the challenge, then left. During the morning, Gladion sent Umbreon to deliver a letter to Ash to accept the challenge. Ash soon came, as Gladion said he wanted to battle him because of his ties with Tapu Koko. As the two had their Rockruff and Lycanroc battle, Team Rocket came and snatched Lycanroc and Pikachu. Ash's Rockruff managed to Bite the net and free Pikachu and Lycanroc. Gladion decided to finish this, as he used the Z-Ring to have his Lycanroc use Continental Crush, blasting Team Rocket away. Since Ash wanted to use the Rock-type Z-Move, Gladion advised him to challenge the Island Kahuna of Akala Island. Just as they were about to continue the battle, Lillie came and cheered for her brother. Since Ash had to go to school, Gladion said they should postpone the battle. He shook hands with Ash and left.
As Ash faced Olivia, who had her Lycanroc use Continental Crush, Ash remembered Gladion and his Lycanroc, the former having the latter use the same Z-Move. Gladion's Lycanroc heard Rockruff's howling on Akala Island. Gladion allowed Lycanroc to go investigate but to be back by nighttime. Gladion went to a cave and sent his Type: Null out inside it. However, due to the strain of its helmet, it acted restlessly. Gladion ran over to Silvally to comfort it and told it that everything would be fine. He exclaimed it would be a problem if someone saw it outside. Sometime later, Silvally acted restless again as it sensed the birth of a young Cosmog named Nebby. Gladion reminded Silvally it would be a problem if someone saw it outside the cave. Gladion managed to calm it down, but it sensed the coming of the Ultra Beast.
Later, Gladion, Type: Null, Lycanroc, and Umbreon were about to battle against a group of Pinsir, but Nebby teleported Ash, Pikachu, and Ash's Lycanroc to his location. They fell on top of the Pinsir who attacked them out of anger. Gladion's Type: Null was able to chase them away, then started to walk too close to Nebby, which frightened the latter to the point of tears. Gladion calmed Type: Null, nicknamed Silvally, down, and asked Ash why he had Nebby. Ash denied that Nebby was dangerous and Gladion became frustrated until Ash tells him that Solgaleo and Lunala trusted him to take care of Nebby. He admitted that Nebby teleported him, Pikachu, and Lycanroc to his location because Ash wanted to show Gladion his Dusk Form Lycanroc, who is neither Midday or Midnight Form. Gladion told them they were at Ten Carat Hill. Ash told Gladion about Lillie's progress, that she managed to touch Pikachu, take care of Snowy, and nicknaming Nebby. Gladion was shocked and told Ash that Lillie was attacked by an Ultra Beast a few years ago, and was saved by Silvally. Due to that incident, Gladion believed Ultra Beasts were not worthy to live in this world, and swore to hunt Nebby down if it showed traits of the Ultra Beasts.
He also wondered what kind of trainer Ash was, since Tapu Koko personally gave him a Z-Ring, owns a strange Lycanroc, and Solgaleo and Lunala entrusted him with Nebby. Ash did not answer his questions, but believed he could learn more through a battle. Gladion used his Type: Null for the first time in an official battle, while Ash used his Lycanroc. Silvally proved to be a powerful opponent, landing some powerful attacks, and dodging most of Lycanroc's despite its heavy mask. Silvally's Crush Claw eventually knocked Lycanroc into a nearby puddle, messing up its fur. With its fur ruined, Lycanroc flied into a fit of rage attacking Silvally without Ash's commands, forcing Ash to restrain Lycanroc. Lycanroc's rage frightened Nebby, causing it to release a powerful screech which cleans Lycanroc's fur, calming it down. Ash and Gladion decide to continue the battle, and Silvally eventually defeats Lycanroc with Crush Claw. After the battle, Ash decided to head back to Professor Kukui's house, while Gladion knew this experience had strengthened both Pokémon. Gladion ordered Ash not to say a word about Silvally to anyone, especially Lillie, before walking away.
A few days later, Nebby teleported Lillie to Gladion's location after she strongly desired to see him again. Gladion was startled, asking Lillie why she's there. Lillie was about to express her desire to spend time with him like before, but his Silvally leapt right in front of her. The sight of it caused Lillie to partly remember the incident that traumatized her a few years ago. Gladion rushed over to a terrified Lillie, but Nebby teleported Lillie back to her classmates before he could reach her. Later, Gladion came to Ash, furious for letting Nebby take Lillie to him. Gladion thought that it would've been better for Lillie if she never remembered the incident. He later returned to his hotel room, where Faba was waiting for him, and ordered "the young master" to return the Type: Null. Gladion refused, reminding Faba of his mistreatment and used Lycanroc and Umbreon to protect Silvally. Faba used his Alakazam and Hypno to battle Gladion's Pokémon. Faba's Alakazam and Hypno quickly overpowered Lycanroc and Umbreon with Hypnosis and Psychic. Gladion attempted to use his Type: Null as a last resort, but Faba's Hypno used Hypnosis to render him unconscious. Gladion struggled to resist the powerful Hypnosis, but his vision became blurry and eventually fell unconscious, as Faba stole Silvally.
The next day, Gladion went to Aether Paradise where he saw his mother, Lusamine, in her office. Gladion angrily demanded to know where Silvally was, but Lusamine was completely unaware of the situation. Though she remembered that it was a Pokémon that Faba created to fight Ultra Beasts, Faba had told her that the project failed. Gladion assumed that Faba had been lying, because Silvally had saved Lillie from an Ultra Beast a few years ago. While the two were searching for Silvally in Faba's office, Gladion informed Lusamine of the incident that happened a few years ago. Gladion furiously pointed out that Lusamine should've known this despite Faba's lies, and chastised her for her obsession with Ultra Beasts had caused Lillie to become unable to touch Pokémon. Lusamine apologized to him, but Gladion stated that he was not the one that she should apologize to. Gladion finds Silvally's Premiere Ball, but heard an alarm coming from the basement. Gladion and Lusamine rushed down there, where they found Lillie being held in the air by Faba's Alakazam's Psychic, and Ash, Pikachu, Snowy, and Nebby being held down by Faba's Hypno's Psychic. Gladion sent out Silvally to save Lillie, who broke free from its mask to save Lillie from Alakazam's Psychic.
The evolved Silvally saved Lillie, causing her to fully remember the incident that happened a few years ago. Gladion equipped Silvally with a Dark-Memory Disc, changing it into a Dark-Type Pokémon, and defeated Faba's Alakazam and Hypno with Multi Attack, freeing Ash, Pikachu, Snowy, and Nebby from Hypno's Psychic. Having learned that the whole ordeal was a misunderstanding, Lillie apologized to Silvally and thanked it for saving her twice, and gave Silvally a hug, much to everyone's surprise. Sometime after Faba had escaped, Gladion was searching for him. He eventually visited his mother in her office, and asked if they found Faba. Lusamine denied, and as Gladion was about to continue his search, Lusamine wanted to thank Gladion and to report they were still searching for Faba, but Gladion ignored her and left. After Faba kidnapped Nebby and disappeared, Gladion arrived at the Pokémon School. Told about Faba's newest incident, Gladion believed he was at Aether Foundation. To catch up to them, Lillie called upon a jet from her mansion. Gladion told Lillie to stay behind, but Lillie wanted to save Nebby too and insisted that she came along. Gladion was surprised by his little sister's determination, and let her come along with Ash, too.
Along the way, they informed Lusamine of the situation. On the way to the basement, Gladion assumed that Faba's plan was to use Nebby to summon another Ultra Beast. When they arrived in the basement, they saw Faba using a machine, trapping Nebby and using its power to create an Ultra Wormhole. While Ash tackled Faba, Umbreon destroyed the machines that was trapping Nebby with Shadow Ball. After Nebby was freed, it transformed, much to everyone's surprise. However, the machine absorbed enough energy to create an Ultra Wormhole and an Ultra Beast appeared - the same Ultra Beast that attacked Lillie a few years ago, which Faba named as UB01: Symbiont. UB01 then attacked everyone, so Gladion sends out Silvally to protect Lillie. UB01 proved to be too strong despite everyone's attempt to get it out of their world, and descended down to try to attack Lillie. Gladion was determined to protect his little sister, by letting UB01 take him away, but Lusamine pushed him out of the way and was taken away through the Ultra Wormhole, leaving Lillie and Gladion horrified. After Lusamine's abduction, Gladion approached Lillie, who was overwhelmed by the shock. While Wicke and Burnet were arguing with Faba, Ash wanted to help Gladion, who replied from then on, the issue became a family matter and did not accept his help. Regardless, Burnet advised them to return to Melemele Island, and the group went back home.
At night, Gladion walked into Lillie's room, who lied to him about going to bed. Gladion knew Lillie was plotting something, looking at her new clothes and new hairstyle. Though Lillie still lied to him by saying it's her sleepwear, Gladion asked her how she would open an Ultra Wormhole. Lillie admits that she did not know, but Gladion admitted he knew of a way. The two went on Silvally, out of the mansion. The next day, they arrive on Poni Island. They find an old door with statues of Rowlet, Litten, and Popplio in front of it. Lillie believed it was a puzzle that they had to solve by pushing the statues in place, but Gladion simply pushed the door open. He assumed it was a trap, and had Silvally push the Popplio statue in place, which revealed a spike trap. Gladion ordered Lillie to be careful and not touch anything. They came to a steep cliff, where Lillie thought there was an invisible bridge connected to the other side, and drops some sand in order to find it. Gladion doubted her, telling her to get on Silvally, as they leapt away. He informed Lillie that there was a bridge, but it was destroyed a long time ago. Lillie started thinking she was slowing her brother down, but decided to continue. Gladion knew that Lillie wouldn't stay put even if he told her, and the two proceed forward. They came to an old ruin, where a group of Jangmo-o, Hakamo-o, and their leader Totem Kommo-o ambushed them.
Lillie sent out Snowy to battle the Jangmo-o, and Hakamo-o while Gladion and Silvally dealt with Totem Kommo-o. Totem Kommo-o's hard scales were too hard for Silvally's Crush Claw, and Totem Kommo-o did not take much damage. Lillie advised Gladion that if Silvally could change into a Fairy-Type, they might be able to beat Totem Kommo-o. Gladion was to equip Silvally with a Fairy-Type Memory Disc, but a Jangmo-o disarmed him and the Memory Disc landed underneath Totem Kommo-o. Lillie and Snowy created a path by attacking the Jangmo-o and Hakamo-o and freezing the ground with Powder Snow. Gladion and Silvally skated across the frozen floor while Totem Kommo-o charged up a Clanging Scales attack. Gladion retrieved the Memory Disc and equipped Silvally, protecting the two from Kommo-o's attack. Silvally defeated Totem Kommo-o with a Multi Attack; Lillie congratulated her brother, but Gladion gave the credit to Lillie. The ceiling began to crumble down on them, so the siblings rode on Silvally to reach the exit, and were saved from falling rubble by an Electro Ball. After they barely make it out to the Altar of the Sunne, Ash and his classmates, along with Professor Kukui, came out, too. Gladion reminded Ash that it was a family situation, but Ash reminded him that people in Alola shared everything, including family situations. Persuaded by Lillie that they could use all the help they need, Gladion permitted them to stay. Suddenly, everyone saw as the Guardian Deities showed up for an important meeting.
The group encountered the Guardian Deities, and asked them to lend the power to open an Ultra Wormhole, since Gladion reminded they were to meet Solgaleo at the place. Gladion watched as the Guardian Deities showed a screen presenting Nebby's creation, and how Ash found it. Gladion became impatient, since they had to save his mother, but Lillie thinks they should wait on what the Guardian Deities have to show them. The Guardian Deities performed a ritual, which caused Nebby to evolve into Solgaleo, which astounded the group. In addition, the Guardian Deities upgraded Ash's Z-Ring, giving it a different slot, and black color. Gladion went on Solgaleo, who opened an Ultra Wormhole to cross into the another dimension. The group arrived into the Ultra Space, where they soon found a bunch of Ultra Beasts, UB01: Symbiont, floating around. The group was to search for Lusamine, who touched Sophocles. They saw Lusamine darker, fused with the Ultra Beast, floating around, and screamed they stayed away from her. Lillie ran to her mother, forcing Ash and Gladion to go after her. Lusamine blocked the way with boulders, so Ash protected Lillie while Gladion's Umbreon destroyed the boulders with Dark Pulse. Gladion believed UB01: Symbiont was the cause of Lusamine's strange behavior, and feared it was draining her energy.
Lusamine floated away, leaving behind a trail of boulders wherever she went. The children used that trail to follow her. Gladion thought that part of her real personality was being shown, because of her life-long dream to meet an Ultra Beast, which made Gladion believe Lusamine wasn't aware she's being controlled. Lusamine started sending Pokémon, so Gladion split with the group to let Ash, Pikachu and Solgaleo advance on to confront Lusamine. Gladion, his Lycanroc, Umbreon, and Silvally faced Absol, who used Ice Beam on Silvally's feet, as well as Mean Look on Lycanroc and Umbreon, immobilizing them. With all three of his Pokémon immobilized, Absol continued to attack them. Gladion equipped Silvally with a Fire Memory Disc, changing it into a Fire-Type Pokémon. Silvally broke free from the ice, and with Absol distracted, Gladion had Lycanroc use Continental Crush to defeat it. However, Absol was restored to full health, due to the Ultra Beast energy powering it up. Gladion realized until UB01 was defeated, this fight would continue on; he left Lycanroc and Umbreon to deal with Absol, and rode off on Silvally. Gladion met up with Lillie, Snowy, Ash's Lycanroc, and Lusamine's Clefable, whom Lillie managed to free from the Ultra Beast's control, while Ash, Solgaleo and Pikachu were facing Lusamine across the toxic goo.
Gladion informed Ash of the situation, and was worried about the others. Lillie went atop Clefable, who was protected from the toxic goo with Magic Guard ability, while Gladion equipped Silvally with a Steel-type Memory Disc to make it immune to that. Lusamine rose up, creating a mountain of rocks. Lillie went to talk things over with her mother, and managed to snap out of her state. However, the Ultra Beast refused to let Lusamine go and made her attack Lillie, who was saved by Gladion and Silvally. The Ultra Beast grew bigger and covered itself with more rocks and spikes, making Gladion believe UB01 was as interested in learning about humans as was Lusamine about Ultra Beasts. Ash wanted to use a Z-Move with Gladion, who already had Lycanroc use Continental Crush against Absol. Instead, Gladion and Lillie distracted Lusamine to let Ash have Pikachu use a new Z-Move, which was 100 times stronger than Thunderbolt. The powerful Z-Move defeated the Ultra Beast, allowing Lillie and Gladion to pull their mother out of it, who was unconscious and covered in black ink. While the Ultra Beast fled, Lusamine woke up, causing all of her Pokémon to stop the battles with the rest of Ash's classmates. Gladion and Lillie help their mother stand up, and Lusamine apologized to them. Gladion watched as his sister cried in Lusamine's arms, relieved her mother had snapped out of her state. The group came out of the Ultra Wormhole by riding on Solgaleo, pleasing Kukui and Burnet for their arrival. However, Gladion was not glad to see that Sophocles had brought a rock from the Ultra Space. In the end, Lillie, Gladion and Lusamine took a helicopter to Aether Paradise.
The night before Professor Kukui and Burnet were getting married, Ash and Pikachu were greeted by Gladion and his Umbreon. Ash invited Gladion to the wedding ceremony, Gladion replied that he was going on a journey, due to his amazement of the Z-Move Ash and Pikachu did in the Ultra Space. Thus, Gladion swore to do the Island Challenge, and asked of Ash to congratulate Professor Kukui and Professor Burnet for him. As Gladion left, Ash promised to him that he would continue his Island Challenge too, and offered to challenge him to another battle someday, causing Gladion to smile and wave goodbye. Later, Ash remembered Gladion and his Pokémon during his battle against Nanu and his Krookodile when Lycanroc became enraged, due to its fur getting dirty. Sometime later, Silvally started acting restless as it sensed the Ultra Beast's presence. Gladion calmed it down and assumed that something was definitely wrong. Thus, Gladion, wearing a new suit, came to Altar of the Sunne to join the Ultra Guardians. He was slightly alerted of Ash's Poipole, who was an Ultra Beast. Regardless, to find the Ultra Wormhole that caused distress, the Ultra Guardians, including Gladion, had their Z-Moves launched at Faba's machine, which cleared the skies. While the scientists were researching, Lusamine showed a ruin inside the altar, showing the Blinding One. She believed the mystery could be solved if they could decipher the ancient code. Suddenly, Wicke called everyone to come back, as everyone saw Lunala emerging from the Ultra Wormhole with a dark Ultra Beast.
To find more out, the Ultra Guardians pursued the Ultra Beast that chased Lunala. Gladion had his Ultra Guardian Pokémon, Noivern, fire Boomburst at the Ultra Beast, which only made the latter mad and emitted lasers. Lillie fell down from her Altaria, but was saved by Lunala. Since the Ultra Beast was dangerous, the Ultra Guardians halted their attacks, and saw as the Ultra Beast equipped itself to Lunala. Gladion tried to have his Noivern use Boomburst and Bite, but Lunala attacked him. Gladion fell off Noivern, but Ash saved him. Solgaleo, known as Nebby, appeared, and attacked Lunala, causing it to defuse with the Ultra Beast, but due to its injuries, it fell down on a beach. An electric net electrocuted Nebby and Lunala, but Gladion and Ash had Silvally and Pikachu free them. In the moment of distraction, the Ultra Beast equipped itself to Nebby and vanished through the Ultra Wormhole. The Ultra Guardians went to their base, where Lunala was recovering. Gladion asked his mother about the Ultra Beast, who did not know much about it, and codenamed it as UB: Black. The Ultra Guardians decided to team up with Lunala and save Nebby, for Gladion wanted to repay Lunala for saving his sister and Nebby for rescuing his mother. Just then, the Z-Rings glew, as Lunala was restored to full power.
The adults came in to see what happened, and the Ultra Guardians informed them they wanted to go through the Ultra Wormhole to save Nebby. Lusamine refused to have them travel through the portal, since it was dangerous, but Gladion reminded her they did go to the Ultra Beasts' world to save her. Lusamine saw his point, and let the group save Nebby. After travelling through the Ultra Wormhole, the Ultra Guardians entered a strange dimension that used to be the home of Ash's Poipole. As they searched for the Ultra Beast, they were attacked by wild Poipole; Ash's Poipole stopped them and told them they're not villains. Gladion tried to stop his teammates, since they'd lose track of Lunala. Ash refused, and just then, an old and weak Ultra Beast, reminiscent of Poipole, came out and the Ultra Guardians rushed over to help it. Gladion listened to the Pokémon's story, and learned that if they were to stop the Ultra Beast, named Necrozma, who was the Blinding One that lost its light, Poipole's world would be enveloped in darkness. Suddenly, the gang heard a crash outside and saw Lunala still fighting with Necrozma, who was still fused with Nebby. Gladion and Silvally attempted to defeat Necrozma, but they were immediately stopped by their teammates, who didn't want either side to suffer. Gladion stood down, and saw the battle between Necrozma and Lunala raging on. To try defusing Necrozma from Nebby, Ash, Gladion Kiawe, and Lana had their Pokémon fire their Z-Moves at Necrozma.
The attacks only made Necrozma stronger, who fired lasers that blew away the group. The group stood back up, and despite having no plan, Ash swore he'd never give up, and the group supported him. The group was contacted by Lusamine and the scientists, who explained that Necrozma needed more power. Since the Ultra Guardians fired their Z-Moves, Burnet explained it needed the power of Pokémon and people, for they, too, were involved in restoring Necrozma ages ago. The Ultra Guardians made a pose, and shared some of their Ultra Aura to Necrozma. They managed to have Necrozma diffused from Nebby, but the former still craved for more power. To protect Nebby and Lunala, Gladion had Silvally use Air Slash to prevent Necrozma from reaching them. As a final measure, Gladion, who received the Z-Crystal from Lunala, passed the Z-Power to it. Along with Ash passing his power to Nebby, he and Gladion had the two Legendary Pokémon use Menacing Moonraze Maelstrom and Searing Sunraze Smash at Necrozma. Necrozma gained the power of these moves, and was restored, its body glowing and restored Poipole's world. With the mission successful, Gladion and others went through the Ultra Wormhole, but left Poipole behind. Gladion trained his Pokémon on Poni Island, until he encountered Lillie. He explained he came to challenge Tapu Fini in a Grand Trial, which made Lillie laugh, for Ash had said the same thing. Gladion smiled, but also told that he wanted to defeat Tapu Fini and have it show him a vision of their father.
Lillie was surprised, remembering that their father passed away in an incident revolving around an Ultra Wormhole. Compared to Gladion's memories of their father's warmth Lillie only knew of things she had seen in family photos, and felt she should not question their mother. Since Gladion wanted Tapu Fini to answer him about what became of his father, Lillie decided to assist him in training. Just as they were to battle, Ash fell down from the sky, and was soon hunted down by Hapu. Lillie stopped the two, and while Hapu complimented her polite behavior, she asked of Gladion to sew his clothes, which have been tattered. Gladion refused, and instead wanted Ash to face him in battle. Ash accepted, and Lillie decided to back down, for Ash was a much more challenging opponent for Gladion. The two sent their Lycanroc out, and started a battle. Gladion's Lycanroc countered Ash's Lycanroc's moves, and noticed the latter had improved, since it was not bothered by its dirty fur anymore. Gladion's Lycanroc used Outrage to attack Ash's Lycanroc, but the latter endured the attacks for the former to get confused. Ash took the opportunity to have his Lycanroc launch Splintered Stormshards Z-Move, which badly wounded Gladion's Lycanroc. However, the latter's confusion was cured, and Gladion had it defeat Ash's Lycanroc with the Z-Move Devastating Drake. Despite the loss, Ash was happy, and promised to catch up with Gladion. Just then, everyone saw Tapu Fini in the sky.
Gladion continued to train on Poni Island, until he was surrounded by a mist. Noting that Tapu Fini was nearby, he rushed away, and encountered Lillie, who was searching for her friends. The two tried to find their father in the mist, due to Tapu Fini's ability to contact the spirits of the dead. The mist subsided, and the siblings found out they were at Hapu's house. They wondered why their father didn't appear in the mist, and were confronted by Hapu, who believed the reason was because their father was still alive. The two were in shock, and Gladion mounted on Silvally to tell his mother about this finding. Before he went away, Hapu told him to return, to challenge her as the newest Island Kahuna in the Grand Trial. He came to Aether Foundation, where he shared the good news with Lusamine and Burnet. Gladion and Umbreon watched the news of the opening of the Alola Pokémon League.
Gladion and Lillie were working with Faba on uncovering documents about their father. Faba saw an old photo of himself, Mohn, Lusamine and Wicke, and told them more about Mohn. Suddenly, they were visited by Lusamine, who took them to their father's old room, where they learned their father's disappearance. This made Gladion remember it was in that very room where his father had pat him on the head. As they were searching, Lillie found Mohn's Z-Ring, which surprised Gladion. He advised her to hold onto the Z-Ring an speak to Hala about it. Some time later, Lusamine and Gladion visited Lillie, and were glad to hear that Hala permitted her to use the Z-Ring. As Lillie showed a notebook about Magearna, which she wanted to reactivate, Gladion remarked that Lillie did become stronger. Eventually, he admitted his goal to his mother: to find his father's Zoroark, who would help him in the search for his father. Lusamine expressed her relief to Gladion, for she felt guilty for not taking care of that Pokémon when Mohn had disappeared.
Hapu fought against Gladion in a Grand Trial, but lost the battle. She congratulated Gladion on his victory over the last Grand Trial. Gladion admitted to Hapu that he wanted to participate in the Alola Pokémon League. However, he explained he had one thing to take care of before the start of the tournament. Later, Gladion searched the island with his Umbreon to find Mohn's Zoroark, but only encountered wild Pokémon like Shiinotic, Vullaby or Fletchling. Umbreon wanted to battle, but Gladion reminded it of their mission. As the two made camp for the night, they were visited by a Fomantis. Suspecting it to be an enemy, Gladion's Umbreon attacked it with Dark Pulse. However, Fomantis merely defended itself, and revealed itself to be a Zoroark in disguise. Gladion was relieved that he finally found Zoroark, who showed him a vision from the past, where Gladion and his family were united. Gladion was happy that Zoroark has returned, and hugged it. Explaining his quest is to find Mohn, Gladion invited Zoroark into his team, who accepted. Gladion arrived at Manalo Stadium. There, he defeated many of Team Skull Grunts, who were pestering him. Gladion commented how that wasn't even a preparation for many heated battles he'd face. At evening, he came to Ash, and greeted him and Lillie, swearing he would win the tournament.
Gladion participated in the Alola Pokémon League with his Silvally. During the Battle Royal, Gladion equipped his Silvally with a Rock Memory to defeat a Talonflame with Multi-Attack. He also encountered Ash, and the two helped each other to defeat a Clawitzer and a Primeape, who were going to attack their Pokémon. Gladion expected Ash not to lose this round, and Ash expected the same thing from Gladion. He passed the preliminary round. When he learned he would face Lillie in the next round, Gladion stared into the sunset with Silvallly. Before the first round battles continued, Lillie and Gladion both swore to give their best in battling each other, despite Gladion being more skilled than his sister. At the battlefield itself, before the siblings began their battle, they became embarrassed to see Lusamine and her scientists cheering them on from the stadium's screen. Gladion sent Umbreon against Lillie's Snowy. Gladion noted that Lillie fought well, as her Snowy protected itself with Hail. He did have Umbreon brace for impact, as Lillie passed Z-Power to Snowy, who used Subzero Slammer Z-Move, that froze Umbreon. However, Umbreon quickly recovered and used Iron Tail, which defeated Snowy.
Gladion faced Jamexio in the next round. He sent Lycanroc to face Jamexio's Mareanie. As Lycanroc put some pressure on the latter, Jamexio had pressed his Z-Ring to let Mareanie use Black Hole Eclipse. Gladion became surprised, seeing the two had a strong bond to pull that out after being cornered. In return, Gladion's Lycanroc used Continental Crush Z-Move to cancel it. With a Stone Edge, Lycanroc defeated Mareanie, so Gladion passed to the next round. Gladion looked at the screen, and was silent when he saw that he'd have to face Kiawe in the semi-finals. Gladion found Team Skull grunts harassing Mimo, and had Silvally attack them with Air Slash. The grunts were annoyed by Gladion, who told them to scram. The grunts, upon seeing his cold gaze, retreated. Mimo thanked Gladion, and introduced herself to him. She announced her brother was going to battle this day, and came to cheer him on, to which Gladion believed she was Kiawe's sister. The two were walking away, with Mimo holding Gladion's hand, which made him remember Lillie. Soon, they encountered Kiawe, who was glad to have found his sister. He also thanked Gladion for watching over her, who didn't want his thanks, as it was nothing. When Lillie appeared, Mimo was surprised to hear that she was Gladion's sister. Gladion, however, departed away.
Moments later, he faced Kiawe at the battlefield, where he sent Lycanroc against Kiawe's Marowak. While Kiawe was glad Mimo had his support, Gladion shied away from his sister. The two started a battle, where Lycanroc continuously used Stone Edge on Kiawe's Marowak. While the latter managed to inflict some damage with Iron Head, it was quickly defeated by Stone Edge. Kiawe sent Turtonator, who repelled Stone Edge with Dragon Tail and stopped Lycanroc with Shell Trap. Gladion anticipated this, as Lycanroc continued attacking with Outage. However, Turtonator managed to defeat Lycanroc with Focus Blast, a move it just learned, to which Gladion sent his other Pokémon - Silvally. Gladion and Kiawe resolved themselves to face Ash in the finals. Silvally attempted to attack Turtonator with Crush Claw, but Turtonator evaded the attack with Shell Smash. As Silvally got its claw stuck in the ground, Turtonator used Inferno Overdrive Z-Move. To endure the attack, Gladion equipped Silvally with a Fire Memory, turning it into a Fire-type Pokémon. As Turtonator became too exhausted, Silvally used Crush Claw to defeat it. As Gladion won the battle, he came to Kiawe, and stated that was a good battle they had. Kiawe smiled, and the two shook hands, for Kiawe realized Gladion was his rival, too. Kiawe swore he would not lose the next battle, while Gladion stated he would anticipate that battle. Later, he and Umbreon watched Ash confronting Guzma in the semi-finals.
Gladion smiled when he saw Ash having won the semi-finals. He walked away with Umbreon to the docks, where he was watching the sunset with the rest of his Pokémon. The night before the finals, Gladion was training his Silvally. He got visited by Lusamine and Lillie, who complimented his hard efforts. Lillie suggested Gladion to get some rest, but Gladion refused, since he had to prepare himself. Lusamine smiled, as Gladion was just like his father, who worked very hard to even forget some other duties. The next day, Gladion faced Ash in the finals. As Gladion sent Silvally, he got surprised by Ash's newly-evolved Melmetal. Melmetal used Double Iron Bash to attack Silvally; the latter evaded the first strike, but got hit by the other one. Silvally went to attack Melmetal with Crush Claw, but was blown away by Melmetal's Flash Cannon. To attempt to confuse Melmetal, Silvally dashed away in a zig-zag pattern, avoiding Double Iron Bash attack and hurting Melmetal with Crush Claw, scratching its head. Moreover, Gladion equipped Silvally with a Fighting Memory, allowing it to use the Fighting-type Multi-Attack.
Melmetal was nearly toppled down, but regained its balance, and earned Gladion's respect. To retaliate, Melmetal endured Silvally's Air Slash and hit it with Double Iron Bash. Since Melmetal was too exhausted, it missed its timing to use Flash Cannon, and got defeated by Silvally's Multi-Attack. Ash sent Pikachu, who used Quick Attack to hit Silvally, who narrowed its head to evade the strike. Pikachu went to use Iron Tail, but was countered by Silvally's Crush Claw. As Pikachu was lying on the floor, Silvally went to use Crush Claw, to which Pikachu ran off by using Quick Attack. Silvally evaded Pikachu's Electroweb, but Pikachu repeated the attack, forming the web in a corner. He went to use Quick Attack, but only to bounce off the Electroweb and strike Silvally with an Iron Tail. Silvally was unable to dodge, and fainted from that attack. Gladion was even more impressed, and then sent Lycanroc, who used Night Daze on Pikachu. Ash was surprised, as Lycanroc could not normally use that move. Pikachu then used Electroweb on Zoroark, who sliced it with Shadow Claw, but it was then shocked by Pikachu's Thunderbolt. The attack caused Lycanroc's Illusion to disappear, revealing the Pokémon to be a Zoroark.
Zoroark used Night Daze, which Pikachu countered with Thunderbolt. Zoroark used a Shadow Claw which clashed against Pikachu's Iron Tail, and keep repeating to use Shadow Claw which was able to hit Pikachu. To continue, Gladion had Zoroark use the Ghost type Z-Move: Never-Ending Nightmare, causing dark hands to come out to hurt Pikachu. In retalaition, Ash had Pikachu use the Normal Type Z-Move: Breakneck Blitz, which resulted in Zoroark and Pikachu's battle ending with a draw. Gladion and Ash then sent their Lyancroc in their final match. Both Ash and Gladion noted how strong the other was, and in that moment, they started to laugh. They admitted this was their greatest battle yet, and went to conclude it: both sides sent Lycanroc out as their final Pokémon. Both Lycanroc used Stone Edge which collided with each other cancel out. Ash's Lycanroc used Acclerock, only hit by counter from Gladion's Lycanroc. Gladin's then went for Stone Edge, which Ash's Manage to doge. When Ash's Lycanroc attempted to use Bite, Gladion's was preparing to use Counter, to Ash's stopped its attack.
Gladion's Lycanroc then attempted to use Stone Edge, which Ash's Lycanroc evaded. Gladion's Lycanroc then lured Ash's close and hit with Counter, only for Ash's Lycanroc to withstand that attack. Both Lycanroc then continue to attack with Accelrock, Stone Edge, and Bite. Gladion's Lycanroc then boosted its power with Sword Dance and attack with Outrage. Ash's Lycanroc went to use Stone Edge, which Gladion's stopped it, but was confused due to Outrage. Gladion's Lycanroc then bit itself, to snap out of its confusion. Gladion's Lycanroc then attempted to use Stone Edge, only for Ash's to break through with Bite and Accelrock. Gladion's Lycanroc then tried to finish the battle with Counter, but got defeated by Ash's Lycanroc used its own Counter to break through and overpowerer Gladion's Lycanroc. The impact itself defeated Gladion's Lycanroc, and Gladion lost the finals. Despite the loss, Gladion congratulated Ash for wining the Alola League and becoming Champion. Ash could not believe he was a Champion, which amused Gladion, and the boys promised to have a rematch one day. That night, Gladion participated in the awards ceremony which was interrupted by Guzzlord, an Ultra Beast that came out of an Ultra Wormhole.
The Island Kahuna asked of Gladion and the rest to evacuate the audience to the docks. Gladion did so, and once the task was complete, he was walking around the arena. He witnessed an Ultra Wormhole opening, from which a white Guzzlord appeared. Hau and Kiawe came to him, seeing the large Guzzlord. Gladion asked of them to retreat, as it was too dangerous, but Kiawe and Hau stated they wouldn't let Gladion battle alone. Gladion blushed, and let them accompany him. Gladion's Lycanroc use Stone Edge to knock Guzzlord down, while Kiawe and Hau sent Turtonator and Decidueye to battle, and had them use Flamethrower and Razor Leaf on Guzzlord to distract it. However, the attacks were not powerful enough to blow Guzzlord away, so Hau had Decidueye hold Guzzlord's claw and Kiawe's Turtonator used Focus Blast to distract it. As Gladion went to have Lycanroc use its Z-Move, Guzzlord uttered a roar that nearly blew the trainers away. Guzzlord attempted to attack them with its claw, but Lillie, Mallow, Lana and Sophocles arrived, and had their Tsareena, Primarina and Vikavolt attack Guzzlord to prevent its attack. Hau, Gladion and Kiawe thanked them for saving them, and the seven trainers used their Z-Rings, blowing away the Z-Moves (with Lycanroc using Devastating Drake). The attacks overpowered Guzzlord, who was blown through the Ultra Wormhole. As the Ultra Wormhole quickly closed, Gladion and the rest cheered for their success.
The next day, Gladion sat with Umbreon to watch the battle between Kukui and Ash. Gladion was intrigued to see Tapu Koko's Guardian of Alola Z-Move, which represented a giant, colliding with Ash's Pikachu's 10,000,000 Volt Thunderbolt. At the end of the exhibtion match, Gladion and Umbreon were happy to see Ash having won the battle. On Lillie's request, Gladion went to meet with his sister inside his father's room. Lillie was glad that he arrived, and showed him a picture inside her father's notebook, displaying Zoroark and Magearna together. She believed Zoroark could be the key to unlock Magearna. Thus, Gladion sent Zoroark out, who was reminiscing about Mohn's room. Upon seeing Magearna, Zoroark used its powers to display a vision of the past to Lillie and Gladion. It showed how Mohn was trying to awaken Magearna, and showed baby Lillie about it. Gladion mentioned Lillie was quite troublesome back then. As the vision ended, Lillie started to cry, for she wanted to meet her father again. This awakened Magearna, who gave Lillie a bouqet of flowers. Lillie hugged Magearna, and Gladion was pleased about her success. Just as Lillie hugged Magearna, her Z-Ring started to glow. She and Gladion witnessed Magearna shooting a purple beam, and it pointed to Mohn's picture. Realizing that Magearna pointed the way to Mohn's location, Gladion became happy, and Lillie went to tell her mother about that.
Few days later, Gladion, Lillie and Lusamine were to board on the ship, to start their journey to find Mohn. Before they departed, Gladion approached Ash, telling him they could have a rematch the next time they would face each other, to which Ash complied. In addition, Rotom took picture of the entire group. On the ship, Gladion, Lusamine and Lillie waved goodbye to their friends and colleagues.
Alola Island Challenge
- Akala Island Grand Trial (Rockium Z)
- Verdant Cavern trial (Normalium Z)
- Vast Poni Canyon trial (Dragonium Z)
- Unknown trial (Ghostium Z)
- Manalo Conference: Runner-up
- Gladion is the only rival to be related to one of Ash's traveling companions.
- Much like Alain, Gladion also:
- Is Ash's main rival in their respective series. In fact, his rivalry with Ash is friendly, from the moment he met him, whereas his rivalries with Gary, Paul, and Trip were fueled by animosity towards each other.
- Left his journey prior to the start of the series.
- Rescued an injured Pokémon sometime in the past (Gible for Alain, and Eevee for Gladion).
- Desired to get stronger to protect the ones they love (Mairin for Alain, and Lillie for Gladion).
- Prefers to be alone.
- Became dedicated to surpassing Ash after witnessing a certain aptitude in strength (Alain witnessed Ash and Greninja transform into Ash-Greninja, and Gladion witnessed Ash and Pikachu using 10,000,000 Volt Thunderbolt).
- Gladion's Ultra Guardians uniform being a different design may be a reference to the long-running Super Sentai/Power Rangers series. Many Super Sentai/Power Rangers seasons typically have the main characters joined by a "Sixth Ranger" midway into the series. Sixth Rangers typically have their costume differ in design from the core team to make them more distinct.
- His recurring phrase when leaving is "Later" (Japanese: じゃな Ja na).
- Gladion is the only rival to have a Legendary Pokémon.
- He doesn't become Guzma's enforcer compared to his game and manga counterparts.