Sanity is a Fear Reaper and a Undead Reaper. He has been on the SS Diablo and is patrolling the port city on Isla Inferno. He makes sure that the Ship of the Line Ghost Ships, controled by the Undead Reapers, don't bring any of Jolly Roger's forces on the island. And if they do then the ship will suffer his hideous rath. He'll show his face and according to legend that you'll be blind forever and that you'll have a scar of his syche on your face. He is a Level 57 Undead Reaper Boss. He appears as a black cloud then when somebody goes past him he appears as his true self. He has also a crew member of the SS Diablo.
He drops, if ever defeated, famed and legendary weapons.