Plumber Marlon is one of the many Plumbers in FusionFall. He can be seen around the Monkey Skyway Agent on The Precipice. He is the brother of Plumber Barry and of Plumber Charley, whom he calls a "good-for-nothing." Plumber Marlon gives the player only one mission, "On the Precipice (Part 1 of 3)," in which he is to look for Charley. When the player finds Plumber Charley, Charley asks the player to take samples from meteorites from Planet Fusion. When Marlon sees the samples, he says they are useless shiny rocks.