Inmates
Originally, Arkham Asylum is used only to house genuinely insane patients having no connection to Batman, but over the course of the 1980s, a trend was established of having the majority of Batman's supervillain opponents end up at Arkham. Nearly all of Batman's enemies have spent some time in Arkham.
Arkham Asylum also features in other DC Universe publications. In Alan Moore's Swamp Thing, The Floronic Man is detained there, and in The Sandman by Neil Gaiman, Doctor Destiny escapes the asylum to wreak havoc on both the real and dream worlds. It has also been featured in varying capacities in a number of high profile DC miniseries events, such as Identity Crisis, Day of Vengeance, Countdown, and Crisis on Infinite Earths among others.
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