Leonard Shelby isn't exactly a name befitting a traditional hero, and Guy Pearce's victim of short-term memory loss resulting from an assault, out for revenge on his wife's supposed murderer, doesn't much fit the mould of a hero either - except, perhaps, in a Greek tragedy. Shelby suffers much throughout the film, to be sure: his last permanent memory is of his wife dying and he covers himself in clue-tattoos so he can remember the clues he's uncovered, and he's manipulated by most everyone he comes into contact with, but he also commits some pretty heinous acts in the name of vengeance. He appears motivated purely by this desire for justice, but as certain things come to light and Lenny is made to face choices he didn't know he'd already made, it becomes clear that Shelby already got the culprit (or might himself be his own wife's killer) and is sending himself on a wild goose chase just to have something to do and avoid becoming a vegetable in a mental hospital. As far as motivations go it's understandable, but morally very iffy, as the human cost of Leonard Shelby just having something to do is very high indeed.
