A senior operative of Section 31 who tried to recruit Julian Bashir and was behind the plan to wipe out the Founders with an engineered disease.
Luther Sloan was an agent of Section 31, a secret organisation operating outside Federation law that claimed to protect the Federation by any means necessary. He first appeared by subjecting Julian Bashir to an elaborate test of loyalty, and afterwards repeatedly tried to recruit the doctor as an agent despite Bashir's revulsion.
Sloan drew Bashir into a mission to the Romulan Empire, where Section 31 manipulated events to remove a senator who opposed the Federation alliance. Bashir later discovered that the group had infected Odo with a disease designed to kill the Founders, effectively attempting genocide to end the Dominion War.
Determined to find the cure, Bashir and Miles O'Brien lured Sloan to Deep Space Nine. Sloan took poison rather than be captured, and the two officers entered his dying mind with a Romulan device to search his memories, retrieving the cure before he died. Sloan remains the face of Section 31's ruthless pragmatism and the moral compromises of war.