Gardevoir first appeared along with her trainer where it battled Magnus and his Absol. Absol used Bite and Diantha winked to Gardevoir, who dodged the attack. Absol then used Quick Attack and Diantha winked again to Gardevoir, who dodged the attack again. Absol kept using Quick Attack and Gardevoir kept dodging the attack. Absol then used Psycho Cut and Gardevoir countered the attack with Shadow Ball. Shadow Ball hit Absol and Absol used Perish Song. Before Absol was able to finish Perish Song, Gardevoir used Moonblast, knocking Absol out and winning the battle. Ash then challenged Diantha and her Gardevoir for a battle against his Pikachu. Pikachu used Iron Tail and Gardevoir dodged the attack. Pikachu then used Quick Attack and Gardevoir kept dodging Pikachu's Quick Attack like she did with Magnus' Absol. Gardevoir also dodged Pikachu's Electro Ball and Thunderbolt. Gardevoir landed Shadow Ball on Pikachu, who was sent flying. Team Rocket then appeared and captured Gardevoir. Gardevoir used Shadow Ball to break the cage but it failed. Diantha mentioned that she was once lost due to a fog when they were filming a movie, she and Gardevoir were able to find each other due to the Mega Stone and Key Stone. When the heroes and Diantha found Team Rocket, Diantha Mega Evolved Gardevoir into Mega Gardevoir, and Mega Gardevoir broke the cage by using multiple Shadow Ball. Mega Gardevoir then sent Team Rocket blasting off by using Moonblast. After Team Rocket blasted off, Mega Gardevoir turned back to Gardevoir, surprising the heroes.
Diantha and Wikstrom had a battle in a stadium in front of masses of spectators with their Pokémon. Wikstrom chose his Scizor, which Mega Evolved at the beginning of the battle with Gardevoir. Mega Scizor attacked with Night Slash, but Mega Gardevoir used its psychic powers to dodge it by gliding across the ground. Mega Gardevoir used the chance to use Moonblast, which defeated Mega Scizor and made Mega Garevoir and Diantha the winners of the match.
After arriving to the heroes to warn them about the crisis in Kalos, Diantha heard about Greninja's form. Diantha asked Ash for a battle, to show this power. Greninja tried to attack Gardevoir with Aerial Ace, Cut and Water Shuriken, but Gardevoir dodged the attacks, even without Diantha telling it to do so. Gardevoir retaliated with Shadow Ball, managing to hit the real Greninja (who used Double Team). After dodging Greninja's Water Shuriken, Gardevoir hit Greninja with Moonblast, hitting it on a tree. Having an idea, Ash had Greninja use Water Shuriken. While Gardevoir dodged the attack, Greninja consequently used Cut, managing to inflict damage on Gardevoir. With this being done, Greninja transformed itself and pushed Gardevoir to the limits, who used Shadow Ball to counter its Water Shuriken and Cut attacks. After being hit by Cut, Diantha had Gardevoir Mega Evolve, who managed to counter Greninja's Aerial Ace. Ash urged Greninja to continue the fight, as Mega Gardevoir stopped Greninja's Aerial Ace with Reflect. Greninja used Double Team, followed with Cut, which Gardevoir stopped with Reflect. Ash pushed Greninja to grow stronger, causing Greninja's watery aura to disappear, as it flew in mid-air with an "X" on its back. Mega Gardevoir tried to use Shadow Ball, but Greninja fired Water Shuriken, which countered the attack and badly injured Mega Gardevoir. In that moment, Ash and Greninja's battle pulses were not in sync and they fell down, having fainted. Just then, Mega Gardevoir was targeted by Team Rocket once again, but managed to blast them off. Diantha then recalled Gardevoir back to its Poké Ball for a long rest after a hard battle.
Due to an outbreak of roots in Lumiose City, Diantha had Gardevoir use Shadow Ball on one of the roots, saving a person's life. She also Mega Evolved it to destroy the plants and rescue the people.
Diantha, Mega Gardevoir and the Gym Leaders came to stop the Giant Rock. Mega Gardevoir, along with Mega Metagross, used Psychic to thwart away the sprouted plants, to let Ash and Alain continue. Since Team Rocket fell off a helicopter that was destroyed by the plants, Diantha rescued them by having Mega Gardevoir use Psychic on them. Once Chespie was rescued, Mega Metagross launched an attack at the Giant Rock, which fused with others' attacks to destroy it. Along with its trainer, Gardevoir watched as Squishy and Z-2 destroyed the Giant Rock and defeated Lysandre.
Ash remembered Diantha and her Gardevoir fighting the Giant Rock with the rest when he was reflecting back on his journey.
|Shadow Ball||The Bonds of Evolution!|
|Moonblast||The Bonds of Evolution!|
|Reflect||Championing a Research Battle!|
|Psychic (move)||Championing a Research Battle!|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.
- Michele Knotz (English)
- ^ XY041: Battling Into the Hall of Fame!
- ^ XY027: The Bonds of Evolution!
- ^ MS017: Pokémon The Movie - Diancie and the Cocoon of Destruction
- ^ XY068: Garchomp's Mega Bond!
- ^ XY118: Championing a Research Battle!
- ^ XY132: A Towering Takeover!
- ^ XY133: Coming Apart at the Dreams!
- ^ XY135: Rocking Kalos Defenses!
- ^ XY136: Forming a More Perfect Union!
- ^ XY140: Till We Compete Again!