Mustard is the undefeated legendary trainer who appears in “The Isle of Armor” expansion for “Pokémon Sword and Shield.”
Mustard is the former Champion of the Galar Pokémon League and the master of the Master Dojo on the Isle of Armor. The game describes him as having held an undefeated championship record for 18 years, making him one of the most formidable trainers in Galar’s history.
When the player arrives on the island, Mustard becomes an important mentor and gives the player a series of training trials. Completing those trials leads to Kubfu, a Legendary Pokémon that can evolve into Urshifu after training at either the Tower of Waters or the Tower of Darkness.
Mustard is also notable because he was once Leon’s mentor. In the expansion’s later battles, he uses his own powerful Pokémon, including a Gigantamax-capable Urshifu. The Isle of Armor was released as the first part of the Pokémon Sword and Shield Expansion Pass on June 17, 2020, adding a new open-world area and dojo-based storyline.