Oatchi is a Rescue Pup, a type of space dog that assists the Rescue Corps. In-game, he is the companion of the player's character, assisting them with transportation, by working like a Pikmin, by performing specialized tasks, and by serving as a secondary leader if the two are separated. His breed of space dogs has long served the Shepherd family, and he obeyed only Erma Shepherd, the captain of the Rescue Corps, until the player's character appeared. Like his owner, he is from the planet Giya.