One of the most senior and respected Security Guards at Arkham Asylum, Cash is only afraid of one inmate-Killer Croc, who severly wounded him and bit off his left hand. However, Cash remained determined to keep the asylum's inmates under control and to conquer the fears of Croc.
When Batman, Frank Boles and another guard escorted Joker, Cash operated the Weapons Scanner. During the Joker's takeover, Cash made his way to the Medical Facility where the room he was in were filled with Joker Gas. Cash and another Doctor survived and Batman managed to clear the room out of gas using the fans. Cash then regrouped with other Arkham Staff and said he'll go with Dr. Penelope Young to the Arkham Mansion in order to obtain her research notes. Inside the mansion however, Cash and Young were ambushed by Joker's thugs. Young fleed and hid in her Office while Cash and fellow guard, Zach Franklin, held off the goons but were apprehended and interrogated of her whereabouts. Batman got into the room, defeating the thugs and then rescued the guards. Cash told Batman of her whereabouts, so the hero rushed to her office.
When Poison Ivy's Plants slowly attacked the Island, Aaron Cash alongside a group of Arkham security staff took cover in the Mansion. Batman went to them and asked for the whereabouts of Killer Croc's lair, Cash told him and explained that food was thrown in from time to time to Croc.
Cash ultimately survived Joker's attack and returned to his post after Joker's defeat. In the end before returning to his post, he was examined by a doctor in the Medical Facility.
- "I want Joker searched again!"
- "So, what's going on? My radio died as you brought Joker in."
- "I don't know. We locked him up, he gets out and more people die. If I had only just 1 minute alone with that animal."
- "I shouldn't have left Intensive Treatment. I would have made sure that freak stayed where he belonged."
- "The comms are screwed. I can't reach anyone."
- "I can't get anyone. I'll keep trying."