Details: One of the thirteen Special Trainers you will encounter at The Battle Tree after completing certain streaks with the multiple of ten in single player modes or team up with in multi-Battle mode is Wally, the former Rival of the Hoenn Region.
Possible Pokemon:
Altaria (Altarianite): Dragon Dance, Dragon Rush, Giga Impact, Earthquake
Altaria (Wide Lens): Cotton Guard, Sing, Moonblast, Dream Eater
Garchomp (Choice Scarf): Outrage, Earthquake, Fire Fang, Crunch
Garchomp (Garchompite): Sandstorm, Stone Edge, Earthquake, Dragon Claw
Magnezone (Bright Powder): Charge Beam, Flash Cannon, Magnet Rise, Thunder Wave
Magnezone (Assault Vest): Thunderbolt, Flash Cannon, Tri Attack, Volt Switch
Gallade (Scope Lens): Psycho Cut, Stone Edge, Shadow Sneak, X-scissor
Gallade (Galladite): Psycho Cut, Close Combat, Rock Slide, Destiny Bond