Yū owned Infernape as a Chimchar. He sent Chimchar out when his movie Shaymin became disobedient as its level was too high for Yū's standards. As Shin remarked about Yū's progress, Yū decided to train Chimchar in order to be able to battle his rival. Chimchar battled an Onix and Onix's Rock Throw hit Chimchar very hard. Chimchar retaliates with Ember but due to Onix's type combination, Ember was proved useless to the Rock Snake Pokémon. Chimchar's next opponent was a Budew. Budew attacked it with Absorb in which Chimchar was unfazed. Chimchar once again retaliates with Ember and this time, it delivered heavy damage on the opponent. When Yū trained Chimchar very hard, it caused Chimchar to evolve into Monferno and again into Infernape before he began his battle with Shin.
As a Monferno
During the battle with Shin, Yū sent it out along with Shaymin as the battle was a Double Battle. Infernape got the first move and Yū commanded it to use Close Combat on Bronzong. Unfortunately, Bronzong increased its defenses so Bronzong took less damage than usual from Infernape. Infernape tries to attack Bronzong again and manages to defeat it. However, Empoleon attacks Infernape out of nowhere, taking it out.
Later on, it was seen battling a Salamence, Haunter and Onix. Yū also sent out Infernape when his Glaceon couldn't handle Golem. Golem also proved to be very powerful against Infernape but Infernape held on due to it holding a Focus Sash. Infernape then finished Golem with Grass Knot.
Infernape and Yū Shirogane
Infernape was sent out in a Tag Battle alongside Shin's Empoleon and against their opponents's Electivire and Magmortar. After its defense was lowered along with Empoleon's by Magmortar's Leer, Infernape goes for Sunny Day but it backfires as Empoleon used Rain Dance. Infernape was then shown to be defeated by the duo. In the rematch, Infernape was the first Pokémon sent out. It, along with Shin's Staraptor, managed to defeat their Electivire and Magmortar. It went on to finish off the rest of their team.
When Shin could not defeat his opponent's Dialga and Palkia. Yū sent out his Infernape along with Garchomp, they managed to defeat Dialga using their combined Dig, but had trouble with Palkia and Giratina. Infernape was then defeated by Giratina.
During the battle against a kid, Yū sent out Infernape when Rotom was defeated. Infernape went for Flare Blitz and aimed it at Dusknoir but Dusknoir blocked it with Protect. While the opponent's Metagross attacked Yū's Glaceon, Infernape tried Flare Blitz on Dusknoir again and the attack managed to get through. Infernape went for the attack a third time on Metagross and took it out. Both Infernape and Snorlax were the only ones left. Snorlax was very tough as it used Belly Drum to increase its attack tremendously. Infernape used Giga Impact on Snorlax but was deflected by Snorlax itself. Infernape went for a powerful punch and finished Snorlax with Giga Impact, which resulted in Yū and Infernape as the winners.
Personality and characteristics
Infernape has been shown to handle many opponents and even held its own against them in many battles.