Fatman, who named himself after the Fat Man bomb dropped on Nagasaki, is a member of Dead Cell specializing in explosives and the first boss character in the Plant chapter (not counting Raiden's encounter with Fortune).
He is an overweight bald man in a bomb blast suit who moves around with his roller skates and is armed with a Glock 18 in addition to his bombs. One of the player's early objectives in the Plant chapter is to deactivate a series of C4 bombs planted within each of the struts surrounding the Shell 1 core. The explosives are revealed to be nothing more than dummy bombs serve to activate the real bomb in basement of the Strut A.
A similar bomb planted in the basement of the Shell 2 Core detonates, killing Fatman's former mentor Stillman in the process. As Raiden meets with him, Fatman reveals that he wishes to surpass his mentor by killing him and blowing up the Big Shell in the process. Fatman then challenges Raiden to a duel at the heliport atop Strut E.
The battle involves neutralizing Fatman while trying to prevent his explosives from blowing up the place. In the ending sequence of the game, Ocelot reveals that Fatman was actually an agent of The Patriots. Stillman's presence in the facility was arranged to motivate Fatman into participating.
