One day, Gladion found an injured Eevee and brought her to Hobbes. Gladion was very concerned about Eevee, though Hobbes promised she would recover if they took her to the Pokémon Center. Eevee was present with Gladion when Mohn and Lusamine comforted their crying baby, Lillie.
Some time later, Lillie, Gladion, Lusamine, Eevee and Cleffa used to spend a lot of time together as a family. Lillie was working at the orchard with her family and the Pokémon, including Eevee, when she was young. In addition, Lusamine kept pictures of her children and their Pokémon, including Gladion, Cleffa and Eevee, in her office.
Gladion was walking through the streets when he was ambushed by three Team Skull grunts. He ignored them, but since the grunts demanded him to hand Umbreon over, he defeated them with his Lycanroc's Stone Edge. As he met Ash and was told he was given the Z-Ring by Tapu Koko, Gladion sent Umbreon to give him a letter that accepted the challenge. During the battle, Team Rocket snatched Gladion's Lycanroc and Ash's Pikachu. To pursue them, Gladion had Umbreon use Dark Pulse, which pierced the tires of the truck they were driving, allowing Ash's Rockruff to rescue Lycanroc and Pikachu.
Umbreon was seen again where she heard Rockruff's howl on Akala Island. After Lycanroc went to investigate, Umbreon and Gladion entered a cave and tried to comfort Type: Null, nicknamed Silvally, who felt uncomfortable with the strain of its helmet. Umbreon and Lycanroc watched as Gladion tried calming his Silvally down, who acted restless. Umbreon was later seen watching Gladion battle Ash with Silvally.
Later, Umbreon was seen with Gladion, who accused Ash for bringing his sister to him on purpose. After Gladion returned to his hotel room, he was confronted by Faba, who commanded him to give back Silvally immediately. Gladion refused and battled with him to protect Silvally. Faba's Hypno blocked Lycanroc's Stone Edge using Reflect, and put Lycanroc to sleep with Hypnosis, while Alakazam defeated Umbreon, who attempted to use Shadow Ball, with a Miracle Eye and Psychic combo. Umbreon was used to help Ash and Pikachu rescue Nebby from Faba's machine. After Nebby evolved, an Ultra Beast appeared from the Ultra Wormhole and attacked the group. Umbreon, along with Snowy and Silvally, prepared to battle the Ultra Beast, named UB01: Symbiont, but watched in horror as the Ultra Beast grabbed Lusamine and carried her into the Ultra Wormhole. Silvally and Umbreon were with Gladion, who wished to know of alternative ways to open the Ultra Wormhole.
Umbreon was used in the Ultra Space to crush some rubble with Dark Pulse. Silvally, Umbreon and Lycanroc were later used to battle Lusamine's Absol, who glowed with an aura, to rescue its trainer. Absol fired Psycho Cut, but was countered by Umbreon's Dark Pulse. Silvally ended up getting its feet trapped in ice, created by Absol's Ice Beam, while the rest of Gladion's Pokémon were paralyzed by Mean Look. Gladion equipped Silvally with Fire Memory, melting down the ice and using Multi-Attack to burn Absol. Lycanroc and Umbreon were freed from the Mean Look. Silvally used Crush Claw on Absol, who retaliated with Ice Beam, only to get countered by Umbreon's Dark Pulse. Silvally used Air Slash on Absol, who was defeated by Lycanroc's Z-Move, Continental Crush. Due to the Ultra Beast's control over Absol, it stood up and continued the battle, with Lycanroc using Stone Edge. Gladion mounted on Silvally, letting the rest of his Pokémon deal with Absol. After Lusamine diffused with the Ultra Beast, Absol and the rest of her Pokémon snapped out of the Ultra Beast's control, thus ending the battle.
Umbreon accompanied Gladion, who visited Ash to tell him he wanted to continue his journey by taking on the Island Challenge. Ash remembered Gladion and his Pokémon during his battle against Nanu and his Krookodile when Lycanroc became enraged, due to its fur getting dirty. In Poipole's world, Umbreon helped join everyone in sharing its light to restore Necrozma's original Ultra form.
Upon arriving at Poni Island, Umbreon was training with her teammates, and later watched Gladion and Lycanroc battle Ash and his Dusk Lycanroc, and congratulated the former two for their victory. Gladion continued training on Poni Island. Suddenly, a mist started to form around them, so Gladion went with his Pokémon through the mist and found Lillie. The group tried to find Lillie and Gladion's passed-away father in the mist, but failed. When the mist subsided, Hapu informed them their father didn't appear in the mist because he was alive. Gladion and Umbreon watched the news of the opening of the Alola Pokémon League.
Umbreon helped Gladion find Mohn's Zoroark using her ability to sense Zoroark's presence even with its disguises. Later, Gladion searched the island with his Umbreon to find Mohn's Zoroark, but only encountered wild Pokémon like Shiinotic, Fletchling or Vullaby. The latter attacked, to which Umbreon fired Dark Pulse and Shadow Ball to damage her. Umbreon wanted to battle, but Gladion reminded her 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. Umbreon noticed her past self as an Eevee, and watched as Gladion took Zoroark into his team.
At the Alola League, Umbreon was used to battle against Snowy. Snowy used Hail, and due to its Snow Cloak ability, it evaded Umbreon's Dark Pulse. Umbreon fired a Shadow Ball, and hit Snowy, who tried to protect itself with Aurora Veil. Since the hail stopped, Lillie pressed her Icium Z, passing the Z-Power to Snowy to have it use Subzero Slammer, which froze Umbreon. Umbreon, however, was flinged in mid-air, and used the moment to deliver Iron Tail on Snowy as the final blow, which allowed Gladion to move to the quarterfinals. With his match against Kiawe being over, Gladion watched with Umbreon the match between Guzma and Ash. Gladion and Umbreon continued to watch the battle between Guzma and Ash. As the latter had won, Gladion smiled, and walked away with Umbreon. At evening, he and his Pokémon observed the sunset, the night before the Pokémon League finals began. Umbreon took part in Gladion's special training before the final battle against Ash began.
While Gladion continued to battle Ash at the Pokémon League, the two guys remembered their past confrontations involving Umbreon. The next day, Gladion and Umbreon watched the battle between Ash and Professor Kukui, and were happy to see Ash having won that battle. Before Lillie, Lusamine and Gladion went on their journey to find Mohn, Rotom took picture of the group, including Gladion's Umbreon.
- Gladion's Umbreon is the first of her kind to have used Dark Type moves.
- ^ a b SM090: Securing the Future!
- ^ a b SM027: A Glaring Rivalry!
- ^ a b SM127: Chasing Memories, Creating Dreams!
- ^ SM048: Night of a Thousand Poses!
- ^ a b SM049: Mission: Total Recall!
- ^ SM116: The Secret Princess!
- ^ a b SM053: Rescuing the Unwilling!
- ^ SM037: Rising from the Ruins!
- ^ SM044: A Dream Encounter!
- ^ SM047: A Masked Warning!
- ^ SM050: Faba's Revenge!
- ^ SM051: Family Determination!
- ^ SM054: 10,000,000 Reasons to Fight!
- ^ SM055: The Professors' New Adventure!
- ^ SM074: Tough Guy Trials!
- ^ SM105: Showdown on Poni Island!
- ^ SM108: Memories in the Mist!
- ^ SM115: The Dealer of Destruction!
- ^ SM131: The Battlefield of Truth and Love!
- ^ SM136: Getting Down to The Ire!
- ^ SM137: The Wisdom Not to Run!
- ^ SM138: Final Rivals!
- ^ SM139: Enter the Champion!
- ^ SM141
- ^ a b SM142
- ^ SM143
- ^ SM144
- ^ SM146