Walrein was the last Pokémon Katie used in the Hoenn League Ever Grande Conference. It was first used against Ash's Swellow and defeated it easily with a powerful and super effective Ice Beam. It then fought Ash's Corphish and defeated it with a Body Slam. It then faced Ash's Grovyle and was about to defeat it despite the type disadvantage. Ash eventually found out that Walrein was weaker without water underneath it for it to swim in. Ash made Walrein freeze the battle field with its own Ice Beam. Grovyle then gained the upper hand and was able to defeat Walrein with Leaf Blade, winning the match for Ash.