Upon hatching, 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 Scraggy right after hatching. Similar to Ash's Snivy and Greninja when it was a Froakie, Riolu also had great expectations for those it bonded with. At first, Riolu wasn't the most open type, as it refused to hatch without finding a Trainer with a matching Aura. Also, Riolu was distrustful towards Ash, due to not recognizing him as the one with the strong Aura it had sensed. However, Riolu 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, Riolu and Ash formed a close bond with each other, much like Greninja and their Trainer closeness to each other through their Bond Phenomenon power.
In addition, Riolu admires Ash's courage, kindness, and determination as it shows to have warmed up to him. Also, Riolu would hold onto Ash's hand or leg as well as mimicking its Trainer's actions, much like Serena's Braixen did during her time as a Fennekin. Riolu even likes being with Ash and doesn't usually leave his side as it sometimes stays outside its PokéBall, much like Ash's Rowlet. Through Ash's influences, Riolu has become very friendly with everyone around it and picked up some of his traits. Also, Riolu seems to have picked up some of Pikachu traits as well as it assumed it was gonna be sent out to battle but it was bummed out that Ash didn't have it battle, although it got over it and choose to cheer for its Trainer on. Riolu seems to admire its evolved form, much like Ash's Lycanroc did when he was a Rockruff.
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 Hashiba. 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.
As a Riolu
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 have 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 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 a 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 side lines in order to watch. Riolu was pleased to see Ash win but was more impressed to see how strong Korrina's Lucario was.
- Kei Shindō (Japanese)
- Riolu is Ash's first Pokémon:
- That Ash hatched from an egg since his Noivern as a Noibat.
- Also to have spent less than one episode as an egg.
- To have known a single move upon hatching.
- Capture of a Generation IV Pokémon since Gible.
- To be a Fighting-type since Hawlucha.
- 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 in Pokémon Journeys, that didn't originate from Generation I.
- That Ash hatched from an egg since his Noivern as a Noibat.
- Riolu's Pokémon Egg is somewhat similar to the 10km Egg in Pokémon GO.
- Its initial usage of Vacuum Wave is similar to that of Aura Sphere.
- In many ways, Ash's capture of Riolu is a way to make up for the other Riolu in the Diamond and Pearl series where he met and formed a close bond with it, but never officially caught it.
- This is a similar case with Ash's Gengar upon its own capture by making up for the Haunter he tried to use against Sabrina in the original series since he never officially caught it either.
- Also, much like with the Aura Sphere Riolu, this Riolu has a connection to Ash's Aura. Additionally, it also attacked him when they first interacted with each other.
At Oak's Lab
At Kukui's house
At Cerise Laboratory