Upon hatching, Lucario as a Riolu was shown to be very determined, using Vacuum Wave on anyone it sees. It also seems very proud and independent, as it refused to be cuddled or cared for despite being a baby Pokémon. It can also be cocky and reckless, picking fights with other wild Pokémon even though it was clearly outmatched, similar to Ash's Scraggy right after hatching. Similar to Ash's Snivy and Greninja when it was a Froakie, Lucario, while it was a Riolu, also had great expectations for those it bonded with. At first, Lucario wasn't the most open type, as it refused to hatch without finding a Trainer with a matching Aura.
Through Ash's influences, Lucario has become very friendly and supportive with everyone around it as it picked up some of his traits, such as eating a lot. Also, Lucario seems to have picked up some of Pikachu's traits as well as assumed it was gonna be sent out to battle but was bummed out that Ash didn't have it participate in the battle, although it got over it and choose to cheer for its Trainer on. In addition, as a Riolu, it admire its evolved form, much like Ash's Lycanroc did when he was a Rockruff. It even gained a rival in Bea's Grapploct. Also, as Riolu, it had a habit of coming out of its Poké Ball on its own, much like Misty's Psyduck, Jessie's Wobbuffet, May's Skitty and Munchlax, Ash's Oshawott and Clemont's Chespin.
But for most part, Lucario has become more stoic and serious upon evolution. At times, Lucario can get provoked rather easily, such as when Cinderace's antics irritated him. Despite this, Lucario is loyal towards anyone who is closest to it and would choose their safety over its own.
Lucario and Ash first met each other when they each responded to each other's auras. Upon hatching as a Riolu, Lucario was cautious and distrustful around Ash since it couldn't recognize his Aura from before. However, Lucario changed its opinion about Ash when it not only sensed his Aura powers, but also when he helped it get out of a tough spot. After that, through their Aura abilities, Lucario and Ash formed a close bond with each other, much like Greninja and their Trainer's closeness to each other through their Bond Phenomenon power. In addition, Lucario admires Ash's courage, kindness, and determination as it shows to have warmed up to him. Also, Lucario, while it was a Riolu, would hold onto Ash's hand or leg as well as mimicking its Trainer's actions, much like Serena's Braixen did during its time as a Fennekin. Lucario even likes being with Ash and doesn't leave his side as it usually stays outside of its PokéBall, much like Ash's Rowlet and Ash's Naganadel when it was a Poipole. Also, Lucario considers Ash its best friend and not only supports him, but also has great faith in him. When Ash was in danger of Chairman Rose's two Pokémon, Lucario, while still a Riolu, jumped in to save him, which led to it evolving.
As a Riolu, Lucario initially pushed Pikachu out of the way when it wanted to battle against the wild Onix. Later on, the two have developed a friendship in which they help train and play with each other. Lucario has a sibling relationship with Pikachu as they would do anything for one another.
As Riolu, it would usually train with Mimey to help its moves. Lucario has a caring relationship with Mimey as it's grateful for what it does for it. Lucario and Mimey seem to be good friends with each other.
Lucario has a very good relationship with Dragonite as it gets along well with it. Also, Lucario supports Dragonite and is impressed with its caring nature for others.
Although they aren't close, Lucario and Gengar do seem to get along well as teammates. Lucario is even good friends with Gengar.
Lucario quickly became training partners with Farfetch'd for battles, much like Scraggy with Iris' Axew and Lycanroc with Incineroar. Also, Lucario and Farfetch'd do have a rivalry with each other but they not only see each other as friends but also teammates.
Much like their Trainers, both Lucario and Cinderace, as Riolu and Raboot respectively, have shown to be good friends. When they have reunited after evolving, the two shared a fist bump along with Pikachu. Despite usually sharing a friendly relationship, sometimes Lucario's seriousness does come into conflict with Cinderace.
As an Egg
Riolu was originally an Egg from Sinnoh that got imported to Kanto. It was passed down from one caretaker to another, but it refused to hatch as it hadn't found a Trainer that was worthy of it. However, at the Vermillion City Pokémon Center, It sensed Ash's aura being transmitted to it during his battle with Hayden. When it sensed Ash's presence at the Pokémon Center as he came to treat his Pikachu, it rolled towards him and Nurse Joy handed it to him. Deeming Ash worthy, Riolu finally hatched during the night.
Upon hatching, Riolu was greeted by Ash, Pikachu, Goh, and Raboot. However, out of distrust and not recognizing Ash as the person who possessed the same Aura, Riolu shot a Vacuum Wave at him then jumped out of the window and ran away from the laboratory. As Riolu left the institute, it encountered a lot of wild Pokémon as it battled them but got attacked by them and had taken a lot of damage. When Riolu encountered an Onix, it was protected by Ash and Pikachu, who were looking for it, as they notice that the Emanation Pokémon was in trouble. While watching Ash and Pikachu battle Onix, Riolu sensed the Aura within him. After realizing that Ash was the one who possessed the powerful Aura it sensed in its egg state, Riolu pushed Pikachu aside and decided to battle with him. Thanks to Ash's commands, Riolu was able to defeat Onix. At the Pokémon Center, Riolu had its wounds healed and decided to come with Ash, which he accepted, thus joining his team.
Riolu was training its Vacuum wave against Mimey's Reflect at Cerise Park before Ash was called by Goh. It joined Ash in helping take care of Goh's Pokémon but notice that their all fighting as there been a food shortage problem. After seeing that the problem was getting worse, Riolu accompanied Ash to investigate the food shortage as they decided to spend the night at Cerise Park in order to find out who's been taking the food. However, Riolu, Ash, and Pikachu all fell asleep during their shift as they woke up that next morning to find out that the bait they left out was gone. Seeing Goh's Pokémon fighting, Riolu, Pikachu, and Raboot tried to break it up but to no avail until Dragonite grabbed everyone. While watching the fighting and when Goh's Golurk went on a rampage when its seal was removed, Riolu tried to help but became stunned when its Vacuum Wave didn't do a thing as it didn't know that Fighting-type moves didn't work on Ghost types. After some of Goh's Pokémon put Golurk's seal back on, Riolu helped Cascoon evolve into Dustox and became amazed to see their evolution. Riolu enjoyed some food with Pikachu, Dragonite, and Goh's Pokémon. However, while playing on Golurk, Riolu and everyone was falling off when the Automaton Pokémon went on a rampage again when its seal came off.
Riolu was later used to battle Matori and her Team Rocket Grunts in an attempt to save the captured Pokémon at the Sinnoh region's Resort Area. However, it was quickly overpowered by Team Rocket's Purugly and was initially knocked out. After Pikachu was taken by Team Rocket, Riolu was with Ash, Goh, and Raboot at the Pokémon Center until they were approached by the Team Rocket trio, who want payback against Matori, in disguise as they put a tracking device on one of the grunts Pokémon. While Goh distracted the grunts, Riolu and Ash came to Pikachu along with the other Pokémon rescue. After all of them were set free, Riolu and Pikachu teamed up with the other Pokémon as their efforts forced Team Rocket to retreat.
Riolu joined its Trainer along with the rest of the team to the Kalos region where Ash was battling in the World Coronation Series Battle festival. Sensing the presence of Aura, Riolu headed towards the source with Ash, who was sensing the same thing, accompanied it as it saw that its evolved form was emitting them. After Ash with Pikachu realized that it was Korrina's Lucario and Korrina arrived, Riolu was introduced to them as it became impressed with its evolved form. Although it wanted to battle Lucario, Riolu and Pikachu obeyed Ash as they sat in the sidelines in order to watch. Riolu was pleased to see Ash win but was more impressed to see how strong Korrina's Lucario was.
Riolu continued his training with Mr. Mime, having learned Force Palm, and managed to finally break through its Reflect. When Professor Cerise decided to surprise them with tickets to a Pokémon World Championship Match in the Galar Region, Ash decided to take Riolu with him. Upon arriving at the stadium, Ash sent out Riolu to watch the battle. Riolu watched the battle intently, watching it closely. After the match, Ash encountered a Galarian Farfetch'd, and after Goh failed to catch it, he decided to battle it himself. When Ash was originally going to choose Pikachu, Riolu showed awareness to what was happening inside of its Poké Ball and popped out of the ball on its own, showing that it wanted to battle. Ash then revealed to Goh that Riolu had also learned Double Team and Reversal. Riolu was eventually knocked to the ground after being hit by Farfetch'd's Brutal Swing, but Ash cheered it on, and Riolu struggled back to his feet. Using a powerful Reversal hit, Riolu knocked Farfetch'd to the ground. Riolu was shocked when Ash began to cheer for Farfetch’d as well. After Farfetch'd got back up, Riolu prepared to finish it, but it ended up fainting after using the rest of its energy just to get up. Riolu then watched as Ash welcomed Farfetch’d to join his team and subsequently caught it. Riolu and Farfetch’d immediately resumed their training afterward.
That following morning, Riolu was eating some of Galar's famous Curry on Rice with its Trainer, Pikachu, Goh, Raboot and the two Farfetch'd. When the food was disappearing, it turned out to be the work of a wild Sobble. It later discovered a wild Silicobra and cheered Sobble on. Afterward, it accompanied Ash and Pikachu in the search for Sobble, only to find an Oddish in a bush. When Sobble was being held captive by Team Rocket, Riolu took part in the battle to rescue the frightened Pokémon. Riolu was later seen having a training match against Pikachu. Ash had Pikachu use Iron Tail and had Riolu use Force Palm to block it, which worked. Riolu then followed Ash and Pikachu after Goh told them that Sobble had gone missing. After finding a group of crying Pokémon, Sobble’s tears soon spread far enough to affect them, and they all began to cry as well.
Riolu eventually entered its first World Coronation Series match against Tony and his Electabuzz, with Ash and Pikachu cheering it on. Despite Electabuzz being an evolved Pokémon, it ended up defeating the former with Vacuum Wave. After the battle, Pikachu showed that he wanted to fight next, but Ash rejected him after saying that Riolu was on a roll with its training. After returning back to Cerise Park, Ash brought out his Farfetch’d to train against Riolu. This time Riolu ended up knocking it out successfully with Reversal. Ash attempted to finish the training session, to which Pikachu became excited, but Riolu wanted to keep on fighting. Goh suggested that Riolu should fight his Farfetch'd as well, much to Pikachu’s dismay. Again, Riolu managed to knock it out by using Vacuum Wave. Ash then attempted to end the training again, but Riolu quickly showed that it wanted to continue, despite being tired. Goh then brought out his Beedrill and the two kept training. The training continued all day until Delia Ketchum made a sudden appearance at the lab. Delia made food for all the Pokémon, and Riolu quickly finished it's so fast that it could get back to training with Ash.
Riolu soon did some training at the Fighting Dojo in Saffron City against both a Hitmonchan and a Hitmonlee. It later took part in the match against Bea's Grapploct, but was defeated from Liquidation. Riolu later did some jogging with Ash and Pikachu until it had partaken in two World Coronation battles where it, unfortunately, was defeated by two multi-limbed Pokémon. It later accompanied the Research fellows in investigating the mysterious sandstorm in the Hoenn Region. Upon encountering a wild Flygon, Ash switched Pikachu out for Riolu since Pikachu's Electric-type attacks were having no effect on the Mystic Pokémon. Finding it challenging to land a hit on Flygon, Riolu sensed its Trainer was in distress. After Goh captured the Flygon, Riolu and Pikachu went to comfort their trainer when he decided to start from scratch. Riolu was later seen enjoying lunch with Ash's current team and Alolan team at the Pokémon School.
Riolu trains against Pikachu until Goh tells Ash that Bea is in Johto. Upon arriving, Riolu watched Pikachu take on Bea's Hitmontop in their rematch. When Grapploct came out, Riolu looked in frustration at Pikachu's next opponent. After Pikachu was knocked out due to Liquidation, it was up to Riolu to take on the Jutsu Pokémon. When it got caught in the Octolock, Riolu used its aura to boost its strength and unleashed a powerful Force Palm. After a collision of Force Palm and Close Combat, both Pokémon were knocked out, resulting in a draw. After the intense battle and during the tea party, Riolu was initially restrained towards Bea, but then Bea's Grapploct gave it a push to encourage it to accept Bea's chocolate cake, so it loosened up and accepted her kind offer afterwards.
Riolu was later sent out to battle Chairman Rose, his Copperajah, and his Ferrothorn. During the battle Copperajah and Ferrothorn proved to be very tough opponents and did a vast amount of damage on Pikachu and Riolu. Just when Rose was about to have his Pokémon finish Ash and Pikachu, Riolu protected them by holding them down, causing it to evolve into Lucario.
Ash commanded Lucario to use Vacuum Wave, but Lucario turns around, uses its aura abilities to communicate with him, and requested to use Aura Sphere instead. Ash accepted its request and uses Aura Sphere to defeat Copperajah and Ferrothorn. Ash, Pikachu and Lucario rush up to the top of the Hammerlocke Stadium to assist Leon in stopping Eternatus' assault of Galar, while also meeting up with Goh and his newly-evolved Cinderace. It then joined forces with the Legendary Pokémon, Zacian and Zamazenta in battling Eternatus until it collapses. Ash and Goh successfuly captured Eternatus and sealed it away for good. The next day, Ash and Goh returned the Rusted Sword and Rusted Shield to the Slumbering Weald and went back to Vermillion City with Lucario, Pikachu and Cinderace.
Lucario was later sent out to combat against Mewtwo alongside Cinderace. Despite their efforts, the two Pokémon and their Trainers were overwhelmed by Mewtwo's power. It soon wound up back at the Cerise Laboratory alongside its Trainer, Pikachu, Goh, and Cinderace.
Lucario was seen taking a nap alongside Cinderace during their meal time.
Ash let Lucario out when they arrived in Castelia City where Ash offered it some of his ice cream, to which it declined. When Cinderace offered some of its sweet to it, Lucario became furious at Cinderace for getting the cream on its fur causing it to slap the ice cream away. Cinderace told Lucario off for slapping its ice cream, But Lucario didn't care. They ended up being angry at each other and walked away. Lucario later noticed Cinderace running after Team Rocket who had captured "Pikachu". Upon being bound together by the orange substance, Lucario and Cinderace flew from one part of Castelia City to the next. When backed up into a corner by Team Rocket's Throh and Sawk, Lucario and Cinderace put their differences aside to combat the two martial arts Pokémon and sent Team Rocket blasting off. Upon returning to their Trainers, the two were shocked to find that Pikachu was with the boys the whole time. Goh soon gave Cinderace some cream buns in which Cinderace took a bite out of one, but Cinderace smudged some cream onto Lucario's face. Lucario was once again provoked, and chased Cinderace in a fit of rage.
- Lucario is Ash's first Pokémon since Noivern to:
- Have hatched from an Egg.
- Have spent less than one episode as an Egg.
- Have known a single move upon hatching.
- Be a Semi-Pseudo Legendary Pokémon.
- Lucario is the first of Ash's Pokémon to be a Generation IV Pokémon since Gible.
- Lucario is the first of Ash's Pokémon to be a Fighting-Type since Hawlucha.
- As Riolu, it was Ash's first Pokémon:
- To be a pure Fighting-Type since Primeape.
- To be a Baby Pokémon.
- That isn't a Pokémon in its fully evolved form to be obtained in Pokémon Journeys.
- That isn't a Pokémon captured by Ash in Pokémon Journeys that originated from Generation I.
- To evolve outside of the region it was caught at since Quilava.
- Lucario is Ash's second Steel-type Pokémon, the first being Melmetal.
- It is also Ash's first non-Mythical Steel-Type Pokémon.
- Riolu's Pokémon Egg is somewhat similar to the 10 km egg in Pokémon GO.
- Its initial usage of Vacuum Wave is similar to that of Aura Sphere.
- Its evolution was teased in the second variant of One, Two, Three and a poster promoting the shift from Sunday to Friday Japanese airing.
- This Lucario shares similarities with a Lucario who served under Sir Aaron:
- Both reacted strongly to Ash's Aura from their confinements; its Egg and The Staff of the Guardian respectively.
- Both are voiced by Daisuke Namikawa in the Japanese versions.
- Both are serious and loyal Pokémon.
- Whilst the Lucario that served Sir Aaron took a liking to chocolate, Ash's Lucario doesn't take a liking to sweets.
- ^ a b PJ021: Caring for a Mystery!
- ^ PJ023: Panic in the Park!
- ^ PJ024: A Little Rocket R & R!
- ^ PJ025: A Festival Reunion!
- ^ PJ027: Toughing It Out!
- ^ PJ028: Sobbing Sobble!
- ^ PJ029: There's a New Kid in Town!
- ^ PJ030: Betrayed, Bothered, and Beleaguered!
- ^ PJ034: Solitary and Menacing!
- ^ PJ036: Making Battles in the Sand!
- ^ PJ037
- ^ PJ039
- ^ PJ042
- ^ PJ044
- ^ a b PJ045
- ^ PJ046
- ^ PJ047
- ^ PJ048
At Oak's Lab
At Kukui's house
At Cerise Laboratory