Diantha/Anime/Main series

Diantha debuted in The Bonds of Evolution!, where she was shown having an exhibition against. With her, Diantha had very little trouble in defeating her opponent's where it was shown she could direct her Gardevoir through mere eye contact. and later encountered Diantha in disguise, trying to get a piece of chocolate cake from a shop. She agreed to have a battle with Ash, but the battle between and Gardevoir was soon interrupted by, who caught Gardevoir and took it away. With the guidance of Diantha's Key Stone, Ash and his friends were able to find Team Rocket. Diantha then Mega Evolved her Gardevoir into Mega Gardevoir, easily breaking out of its confinement and sending the Rocket trio blasting off again.

Just like in the games, Diantha is a famous movie star. She starred in a movie titled "". She is also a fan of desserts, going out of her way to sample the local delicacies whenever she arrives in a new town. Her manager is Kathi Lee.

She was seen in a fantasy in Summer of Discovery!, where it is also revealed that she and Gardevoir participated in the Pokémon Summer Camp back when Diantha was younger and Gardevoir was a.

Diantha made a brief appearance in the beginning of Diancie and the Cocoon of Destruction, where she was shown battling Wikstrom. She also appeared in a flashback in Garchomp's Mega Bond!.

In Championing a Research Battle!, Diantha spoke with Olympia about the threat that Kalos was to face in the future, during which Olympia showed her a vision of. When Olympia mentioned Ash and his friends, Diantha decided to track them down and let them know what she had heard, eventually meeting them in the middle of a training session. When she was informed about the mystical power of Ash and, she requested to battle Ash again. Diantha and Gardevoir initially held the upper hand, but as the battle continued Ash and Greninja (which eventually transformed into Ash-Greninja, to Diantha's shock) kept doing better. Diantha eventually decided to get serious and Mega Evolve her Gardevoir. Ash and Greninja, however, managed to perfect their transformation and knocked Gardevoir off its feet. But before the battle could continue, Ash and Greninja both passed out. Team Rocket then tried to get their hands on a weakened Gardevoir, but Diantha easily sent them blasting off again. After thanking Gardevoir for its efforts and making sure Ash and Greninja were okay, Diantha left, but could not help but question the nature of Greninja's transformation and the role Ash and his friends were to play. She also appeared again in another flashback in the following episode.

Diantha made further appearances since A League of His Own!, where she stood in the middle of the Lumiose Conference's stadium and welcomed the participants of the Conference. In Analysis Versus Passion! and A Riveting Rivalry!, she watched Ash's and Sawyer's battle in the semifinal round. In Kalos League Passion with a Certain Flare!, she was watching, along with Professor Sycamore, as Ash and Alain each walked towards their respective sides of the battlefield in the Lumiose Conference's stadium, for the final round of the Conference. In Finals Not for the Faint-Hearted!, she watched the start of Ash and Alain's battle in the final round of the Lumiose Conference; and in Down to the Fiery Finish!, she watched the battle's conclusion.

In A Towering Takeover!, Coming Apart at the Dreams!, and The Right Hero for the Right Job!, Diantha was caught up in Team Flare's attack on Lumiose City.

In Rocking Kalos Defenses! and Forming a More Perfect Union!, Diantha helped destroy the Giant Rock.

She appeared again in a flashback in Till We Compete Again!.

