Dorian (Japanese: リュウジ Ryūji) is a character of the day in the Pokémon anime. He appeared in Just Add Water.
Dorian is a Water-type Pokémon Trainer who runs the unofficial Coastline Gym near a beach south of Blackthorn City. Dorian puts on synchronized swimming shows with his Pokémon because he's a big fan of The Sensational Sisters - Daisy, Violet, and Lily. Misty in particular was enraged by Dorian's statement that Lily was prettier than she was. Dorian defeated Ash in a battle, but Dorian later respected Misty after she showed off her Psyduck's powerful Psychic attack.
Dorian's Gym battles take place underwater, with Trainers using scuba diving gear to remain with their Pokémon.