Sewer Urchin is an unusual fellow: he wallows in the sewers, and yet, he loves it. He is the protector of the sewer's people, and unafraid to risk his life to save his home. He is often mocked by Die Fledermaus for his smell and habits, and is sometimes excluded from missions because nobody wants him around. He and Arthur seem to have a good friendship, as he answered Arthur's request to help him free Tick from Mr. Mental, and when he saved Arthur from the superhero, Doorman.