Dr Harleen Frances Quinzel was an Arkham Asylum psychologist who thought she had a shot at curing Batman's insane nemesis The Joker. Obviously that didn't work out too well.
Harley Quinn is one of the more distinctive super villains to appear in Sony Online Entertainment's DC Universe Online for several reasons. For one, she started life as a character created solely for the animated Batman cartoon, making the leap into comic book continuity later in life.
She's also one of the most cosplayed comic book females of all time. Seriously, look up Harley Quinn cosplay in Google. It's ridiculous.
Players will be able to fight against, alongside, and in some cases as Harley Quinn when DC Universe Online launches next month on the PlayStation 3 and PC.