Arkham Asylum was the facility where the criminally insane of Gotham City were interred.
At some point after District Attorney Harvey Dent was scarred by Boss Moroni and driven mad, he was captured by Batman and interred at Arkham Asylum. On the second anniversary of his capture, Dent, who identified himself as Two-Face, escaped and set out to rob the Second Bank of Gotham, in a plan to lock and kill Batman in a vault that was filled with the acid that had scarred himself.
Months later, Two-Face was killed after he plummeted to his death on Claw Island, but his partner in crime, The Riddler, who was criminal mastermind, Edward Nygma, was captured by Batman and Robin and was sent to Arkham Asylum for an unidentified sentence. Dr. Chase Meridian was called to Arkham to consult on Nygma's condition by Dr. Burton. Nygma's final appearance ended up with him in a baggy straitjacket along with his head bandaged. After she witnessed Nygma's total loss of sanity, Chase later informed Bruce that his secret was safe (as the Riddler had previously learned Batman's identity from The Box).
After he was captured by Batman, Mr. Freeze was stripped of his special cyrosuit and had to be wheeled to his cell in a cryo-casket.
Two cruel Arkham guards shoved Freeze into a beam of freezing temperature that was his only way of survival. Freeze tried to escape, but was in normal temperature without his suit; it made him weak and would kill him, and he went back choking to the cold area.
Later, Freeze was rescued by Poison Ivy and Bane. Ivy killed the guards with her poisoned kiss and Bane returned Freeze's cryosuit back to him. All three escaped by shattering the walls with ice and jumping into the river. They formed a criminal alliance, but Ivy betrayed Freeze by destroying the cryo chamber that held his wife, Nora, whom Freeze tried to find a cure for and blamed Batman for her death. After she was defeated by Batgirl, Ivy was taken to Arkham Asylum where she sat playing Loves Me Not with one of her plants.
Freeze then entered, after he was defeated again by the Terrific Trio. He was friendlier to the world that he found out from Batman that Ivy had pulled the plug on Nora's cyro chamber, but Batman restored her and had her delivered to the Arkham lab where Freeze could continue his research. Freeze told Ivy that he was her new cellmate who would make her life a living hell for what she did to Nora.
- Edward Nygma/The Riddler
- Victor Fries/Mr. Freeze
- Pamela Isley/Poison Ivy
- Jervis Tetch/Mad Hatter (Confirmed in Batman & Robin Novelization)
- Jonathan Crane/Scarecrow (Confirmed in Batman & Robin Novelization)
- Maxie Zeus (Confirmed in Batman & Robin Novelization)
- Harvey Dent/Two-Face (former patient)
- The Ventriloquist (assumed, see below)
Behind the Scenes
- The Riddler and Two-Face did not appear in Batman & Robin, but two of their costumes appeared in Arkham's Criminal Property Locker.