Aaron Cash (Earth-4678)

"It's good to see another friendly face. Hell, there aren't that many left in this town."

- Aaron Cash

Aaron Cash is one of the most senior and respected former security guards at Arkham Asylum. Cash is only afraid of one past inmate - Killer Croc, who severely wounded Cash and ate his left hand during a riot at the asylum. Cash remains determined, however, to keep the asylum's inmates under control and conquer his fears of Croc. After the closure of Arkham, Cash returned to the GCPD, his former workplace.

Source

 * https://arkhamcity.fandom.com/wiki/Aaron_Cash