Plumber Marlon is one of the many Plumbers in Fusionfall. He can be seen around the Monkey Skyway Agent in The Precipice. He has a brother named Plumber Charley, who he calls "Good-for-nothing". 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. Plumber Marlon only gives the mission: On the Precipice (Part 1 of 3) to look for Charley.