Psycho-man

Deadpool Kills the Marvel Universe
Psycho-Man, in control of Dr. Benjamin Brighton, a doctor at the Ravencroft Institute took Deadpool into his 'care', attempting to control Deadpool and make him a more efficient killer. Instead, he released a third voice deep in Deadpool's subconscious, which convinced Deadpool to kill the world's heroes and villains. Psycho-Man was his first victim, and was killed by being crushed on a table by Deadpool.