Wally

The character Wally, who you meet early on in the game, can be thought of as a rival since he pops up a few times in the story and can be refought after you beat the Pokemon League. You first meet him in Petalburg City as he prepares to travel to Verdanturf Town, wanting a Pokemon to keep him company. Your father Norman tasks you with helping him catch a Ralts in the grass outside the city.

Battle #1: Mauville City

Details:
Before you can challenge Wattson, you will have to face Wally who believes he has gotten well enough to begin a quest similar to your own. His Ralts isn't very powerful so this shouldn't be a hard battle.

Pokémon Trainer Wally Ralts
Battle Type
Single Battle
Level 16
Battle #2: Victory Road

Details:
You don't see Wally again until the end of Victory Road. He challenges you with a well rounded team this time. Be careful as this can be a very taxing fight before you can get to a Pokemon Center.

Pokémon Trainer Wally AltariaDelcattyRoseliaMagnetonGardevoir
Battle Type
Single Battle
Level 44Level 43Level 44Level 41Level 45
Trainer Eyes Rematch

After beating the Pokemon League Wally can be refought once per day. On each new challenge his team's levels grow by 3 until maxing out at 12 levels above what they were the first time you fought him on Victory Road.

Pokémon Trainer Wally AltariaDelcattyRoseliaMagnetonGardevoir
Battle Type
Single Battle
Level 56Level 55Level 56Level 53Level 57
Trainer Eyes Rematch