The eponymous protagonist of the 2000 AD strip Ulysses Sweet is a maniac for hire, an insane intergalactic assassin based on the planetoid Solonik-5, with an unfortunate tendency to kill his employers before they can pay him.
He has a psyche-chip in his head which the Solonik authorities will use to kill him by remote control if he spends more than two hours on the planet's surface. The chip, an Artificial Intelligence based on a dead psychiatrist, also acts as his therapist.