Arnold Etchison is a serial killer who was convinced that his family was evil, Arnold Etchison believed that he absorbed something of their life force when he killed them. He was apprehended and incarcerated in Arkham Asylum.
On his escape (when Bane set all the inmates free), he encountered the second Batman, and in an encounter with him was allowed to die, perishing when he fell into a vat of molten metal, a fate which he could easily have been saved from..
