Leaked PlayStation 3 Trophies have suggested new Batman: Arkham City DLC will be centered around Harley Quinn and let players take control of Robin.
The Trophies, which were uncovered by PS3Trophies.org, indicate the Harley Quinn themed DLC will be a mini-campaign as opposed to just another set of Challenge Rooms.
Whether or not the insane clown groupie will be playable is still unconfirmed. However, one of the Trophies tasks players with using "5 different Quickfire gadgets in one fight as Robin," so it looks like we'll be taking control of the Boy Wonder at some point too.
Tim Drake appears as a playable character in Arkham City, but can only be used in Challenge maps. His transition into full story DLC could mean other characters, such as Nightwing, might get the same treatment. We've got our fingers crossed.
In February footage from Day 1 Studios' Gotham by Gaslight appeared online, providing a peek at the cancelled project.