Fuse's Lair is the overall final level of the game and is where the player can find the highest level monsters, the most infected patches, and the main antagonist, Fuse. It is the most infected area in the entire game. It is only accessible via The Precipice, and the Green Maw. There are no NPCs, no shops, no Monkey Skyway Agents; nor are there any S.C.A.M.P.E.R.s. There is no infected zone in this section and only three Fusion Portals, leading to Fuse's Hall, Fuse's Labyrinth, and Fuse's Throne. Retro adds a fourth portal: Fuse's Back Door. Unless players have got the power and stamina, they should not go in there alone, or they will regret it!