Assassins

Since an act of assassination often borders on the suicidal, murderers-for-hire have frequently been drug addled, as the term "assassin" attests. Having evolved from the Arabic word "hashshashshin," meaning “hashish eater,” it is clear that even when the Moslems were fighting the Christians during the Crusades, murder came easier to someone who was not in a normal state of mind. If you don't really know what you're doing and no longer appreciate what dangers await you, there's nothing to fear, right? Natural human misgivings give way to a drug-stoked, drug-benumbed resolve.

“It was easier to move the hearts of the multitude than to avoid the single assassin.”

Tacitus, Histories (100 AD).

(See Berserk.)

Scale of 1 to 10: 1. Risks high, pay low, history usually unsympathetic.