“Look out everybody, things are about to get awesome!”
Madmen are a part of the Darksider scav gang found in Triton Flats in Borderlands: The Pre-Sequel. They are found only in the central building in Triton Flats, which houses a Catch-A-Ride station and the level's Fast Travel.
Madmen are the Darksider equivalent of Lunatics, and behave nearly identically - preferring melee attacks, divebombing the Vault Hunters from afar, and throwing ranged buzz-axes. They differ primarily in their skin, which is a darker purple, with a dark helmet reminiscent of a welding helmet.