Jonathan Crane (Earth-8150)

"Though it is simple to bring on, you cannot escape from fear. For fear is not a delusion. You are a sapient mortal condemned to die, and time is against you!"

- - Scarecrow

Doctor Jonathan Crane is a former professor at the Empire State University who developed the fear toxin, a chemical weapon which brought the worst of fears in people. He was eventually fired duo to his illegal experimentation on the college's students. Becoming a doctor at Arkham Asylum, Crane developed the persona of Scarecrow, becoming a recurring foe of Batman, his toxin testing the dark knight into overcoming his greatest fears.

The Scarecrow
"He calls himself "Scarecrow." Psychologist turned psychopath. He preys on the innocent and instill them with fear. When I chose to wear my... costume, it was to prey upon the criminals, and instill them with fear. The irony is not lost on me..."

- - Batman to Robin

Personality
"Without fear, life is meaningless..."

- - Scarecrow