Fatman is an explosives expert and one of the Dead Cell members who, along with Vamp and Fortune, takes over the Big Shell in Metal Gear Solid 2: Sons of Liberty. He does not know the true purpose behind the events at the Big Shell and only came to demonstrate his skills as an "artist" to the world. He was taught by a famous explosives expert, Peter Stillman. Stillman is brought to the Big Shell by SEAL Team 10 due to his knowledge of Fatman's methodology regarding explosives and assists Raiden and Snake by providing coolant canisters and instructions on how to defuse the bombs that Fatman scatters around the Big Shell.
Fatman confronts Raiden on top of Strut E of Shell One. He travels around the area planting small packets of C4 that Raiden must neutralize with coolant in the same manner that he neutralized Fatman's other bombs. As Fatman wears an anti-explosive suit, he can only be hit in the head, thus Raiden must knock him down to get an accurate shot. But even after his defeat, Fatman doesn't give up; he states that he has planted one more big C4 charge and that it is near by. Fatman is actually laying on top of it, and once it's defused, the fight is over.
- "Fatman" was the name of the atomic bomb used to destroy Nagasaki in World War II.
- Fatman is a fan of manicures and during his fight with Raiden he has pink fingernails.