Origin
Kevin first appears in Adventure Time: Marceline and the Scream Queens, in a short story about Marceline the Vampire Queen and Princess Bubblegum. In the story, Marceline is becoming hungry, and there is no red in sight. Princess Bubblegum produces Kevin, a machine she created to help Marceline by painting everything red for her. This leaves Marceline free to perform at her next concert without having to worry about finding food. But when the girls get back from their gig, they see that Kevin has painted a beautiful mural, using every colour but red. He explains that he was trying to paint how the music made him feel, and Princess Bubblegum tries to make him understand that it is okay for him to have fun and express himself, but only after he takes care of his responsibilities first.