Amadeus Arkham

History
Amadeus Arkham was the only son of mentally-ill Elizabeth Arkham, Amadeus watched his mother struggle with her illness for years, which drove him to become a psychiatrist. Years later, having earned a residency at the Metropolis State Psychiatric Hospital, he returned home, and having found his mother to be growing worse, aided her in committing suicide. After her death, he became the sole owner of her home, the Mercey Mansion, which he decided to turn into a facility for the mentally ill. He gave up his practice at MSPH and moved his wife Harriet and daughter Constance into the mansion.

During the remodeling process, one of Arkham's former patients, Martin "Mad Dog" Hawkins, escaped from Metropolis Penitentiary and broke into the Arkham family living quarters. Amadeus returned home that night and discovered both his wife and daughter had been raped and murdered, with Hawkins' nickname carved into Harriet's chest. When the Asylum opened that November, Hawkins was captured and became one of its first inmates. Amadeus insisted on treating him personally. After six months of treatment, Amadeus could see no improvement in Hawkins and killed him with a lethal dosage of electroshock therapy. The incident was ruled accidental but was only the beginning of Amadeus' slide into insanity, and eventually, he ended up dying as an inmate in his own asylum.

Batman: Arkham Asylum

 * Because the character is deceased he doesn't physically appear in the game but his character profile is unlockable and the player can find his grave in the Asylum's cemetery.