In Persona 3 Portable, if the player chooses to play as the female protagonist at the beginning of the game, Igor will eventually present a choice between a male and female Velvet Room attendant. If the player selects the female attendant, the game will continue on with Elizabeth; the same attendant found in the male's side, and in earlier versions of Persona 3. However, if the player chooses a male attendant, Theodore is introduced instead.
Theodore shares all of the same responsibilities and performs all of the same actions as Elizabeth. His primary role is to keep the player's Persona Compendium, register new Personae, and summon Personae for the player for a fee. He also presents the player with a series of quests ranging from item hunts in Tartarus to escorting him out on dates around Iwatodai and Tatsumi Port Island.