Steven first used his Metagross when Alain challenged him for a battle. Alain used his Charizard against Metagross and Alain immediately Mega Evolved his Charizard. After Mega Evolving, Charizard used Flamethrower. Steven ordered Metagross to use Psychic and Metagross directed Flamethrower into the sky. Steven then Mega Evolved Metagross and Metagross used Flash Cannon. Charizard was able to block it but not without taking damage. Charizard used Dragon Claw and slammed Metagross into the ground. After taking damage, Metagross used Meteor Mash and slammed Charizard into the mountain. Charizard recovered from the attack and used Blast Burn. Metagross however was able to endure it and surprised Alain and Mairin, who was watching the battle. Metagross then used Meteor Mash again and Charizard Dragon Claw. They were about to clash when a Flamethrower interrupted the battle. The Flamethrower was revealed to come from a Pyroar by a man named Lysandre who stopped the battle. After Lysandre came, Metagross changed back into its normal form. Later on, Steven sent and Mega Evolved his Metagross to catch Alain's Mega Charizard, who was hit by Mega Rayquaza.
When Alain sent Charizard to battle Kyogre and Groudon, Steven sent his Metagross to help Charizard and both triggered the Mega Evolution. Mega Metagross battled Primal Kyogre, hitting it with Flash Cannon. Primal Kyogre retaliated with Origin Pulse, but Mega Metagross dodged and hit it with Meteor Mash. In return, Primal Kyogre bashed Mega Metagross on ice, then got hit by Ice Beam. Seeing Alain and Mairin were in danger, Mega Metagross used Protect to shield them from icy boulders, then shattered some by using Psychic and Flash Cannon, along with Chespie's Pin Missile. Once the crisis was over, Chespie high-fived Steven's Metagross for the teamwork.
Lysandre explained to Alain all the battles he had with trainers that wielded Mega Evolution was to collect the energy required to control Zygarde.
When Team Flare attacked Lumiose City, Steven and his Metagross arrived to help Serena, Mairin, and Professor Sycamore rescue Chespie from the Lysandre Labs. His Metagross battled Mable's Weavile by using Meteor Mash, but missed and destroyed a building. Though Mable was joined by some Team Flare Grunts, Metagross used Flash Cannon to stop their Sneasel and Houndoom's Dark Pulse and Mable's Weavile's Icy Wind attack. Later, it used Psychic to lift the grunts, saving the group once more.
Steven sent his Metagross to battle the Megalith, alongside Serena's Braixen and Professor Sycamore's Garchomp. Steven and Sycamore Mega Evolved their Pokémon; Mega Metagross used Flash Cannon on the Megalith, which blocked the attacks with the plants. As Mega Garchomp repeated her attack, the plants grasped and bound her and the other Pokémon. Fortunately, Alain's Mega Charizard used Flamethrower, which freed Mega Metagross. Continuing the battle, Mega Garchomp fired Flash Cannon, but was once more bounded by the plants. The Gym Leaders arrived and had their Pokémon launch attacks at the Megalith, which freed the Pokémon. Mega Metagross, along with Mega Gardevoir, used Psychic to thwart away the sprouted plants, to let Ash and Alain continue. Once Chespie was rescued, Mega Metagross launched an attack at the Megalith, which fused with others' attacks to destroy it. Along with its trainer, Metagross watched as Squishy and Z-2 destroyed the Megalith and defeated Lysandre.
Sawyer remembered how Metagross battled against Kyogre and Groudon, who wanted to obtain the megalith, which may not have been destroyed after the recent battle.
Ash remembered Steven and his Metagross fighting the Megalith with the rest when he was reflecting back on his journey.
|Psychic (move)||Mega Evolution Special II|
|Flash Cannon||Mega Evolution Special II|
|Meteor Mash||Mega Evolution Special II|
|Protect||Mega Evolution Special III|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.
Kenta Miyake (Japanese and English)
- ^ Pokémon: Mega Evolution Special II
- ^ Pokémon: Mega Evolution Special III
- ^ XY075: Rivals: Today and Tomorrow!
- ^ XY133: Coming Apart at the Dreams!
- ^ XY134: The Right Hero for the Right Job!
- ^ XY135: Rocking Kalos Defenses!
- ^ XY136: Forming a More Perfect Union!
- ^ XY138: The First Day of the Rest of Your Life!
- ^ XY140: Till We Compete Again!