For $7 you can play as Nightwing in Batman: Arkham City's challenge mode, one of two character DLCs planned for November. The Nightwing pack is in the PSN store and Xbox Live Marketplace now, and Robin arrives November 22.
Nightwing is complete with his own brutal combat animations and set of wonderful toys, including stun batons and wrist-mounted dart guns. Watch him kick, flip, and bludgeon his way through the video below.
For the uninitiated, Nightwing is Dick Grayson, an ex-circus acrobat and the first Robin. As Nightwing, he stepped out of Batman's shadow to become a solo vigilante. Since then, Grayson has had center stage in his own series, and even taking up the mantle of Batman in Grant Morrison's comic series Batman and Robin, in which Bruce Wayne is missing and believed dead.