Gretchen Whilster

Gretchen Whistler was one of the medical staff at Arkham Asylum.

Batman: Arkham Asylum
She displays much commitment to restoring the sanity to the inmates of Arkham, and is seemingly not intimidated by the fearsome Killer Croc, despite his best efforts to scare her. It is unknown if she survived the Joker's takeover, but as she was left in a secluded room with armed guards, it seems likely.