Aaron Cash is one of the most senior and most respected guards at the Arkham Asylum. Cash is afraid of only one inmate, Killer Croc. Croc severely wounded Cash once and took his left hand during a riot at the asylum. Following losing his hand, Aaron spent several weeks in a depression, before returning to Arkham Asylum, after which he faced his fear of Croc before marrying a woman named Maria and having a son named Thomas. He next survives the destruction of Arkham Asylum and returns to the asylum after it's rebuilt by Jeremiah Arkham.
Major Story Arcs
When Jeremiah Arkham rebuilds Arkham Asylum he is contractually obliged to keep Aaron as the Head of Security, although Jeremiah does not believe that Aaron is a good fit in his new Asylum. One of the first inmates secured in Arkham is Killer Croc, and Aaron takes great pleasure in shocking Croc with his new implant. Then when Croc's cell breaks down and Aaron takes more pleasure in watching Croc almost drown.
Later, Black Mask's assistant Alyce Sinner, takes over the Asylum and Croc escapes. Killer Croc hunts down Aaron and just before he eats the guard, the implant comes back online and Aaron shocks him into submission. Aaron then tells Batman about Sinner taking over Arkham Asylum from under Jeremiah's nose.
Later when Jeremiah is imprisoned in his own Asylum, it is Aaron who comes to the apparent rescue of Jeremiah, when is is atacked by Mr. Zsasz..
Titans: Family Reunions
When Deathstroke and his team of Villains for Hire break into Arkum Asylum, things go wrong and several prisoners are let loose in the Asylum and they start a riot. Aaron tries to convince Alyce Sinner that she is nuts for not acting quickly and not calling for help. Sinner reprimands Aaron for using the term "nuts". Aaron is later seen at Dr. Sinner's side when they try to take back the Asylum. He pleads with Deathstroke to help but the villain just walks away saying this is a job for Batman.
The Night of Owls
For more information see: The Night of the Owls
Aaron is present when the Court of Owls comes to Arkham to kill Jeremiah Arkham, and Aaron helps Batman stop them, but he can not stop Batman from taking Jeremiah away for safety.
Seeds and Dirt
Backup story in: Detective Comics #14
Aaron is on duty when Poison Ivy breaks into Arkham to break Clayface out. Aaron is one of several guards knocked out by Ivy, before she finds Clayface's cell.
For more information see: Detective Comics #18
Cash is there when Batman lets The Penguin walk out of Arkham. Cash then informs Batman that Mr. Zsasz is missing.
In Other Media
Batman: Arkham Asylum & Arkham City
Aaron Cash appears in the video game Batman: Arkham Asylum where he was valuable in passing information of the Asylum and its inmates to Batman. He later appears in the sequel Batman: Arkham City.