He's the new Chaos Sorcerer of Nurgle that they've added to their line, and you bet your bottom dollar that I ordered one. He's going to act as either a Sorcerer of Nurgle, or as a Lord with Mark of Nurgle and a Daemon Weapon.
This model looks sweet as hell, and I'd encourage anyone with a love for Chaos Space Marines or, more specifically, Nurgle Marines to go order one. He's currently going for £10.00 (about $20.00). You'll find him listed on their "New Stuff!" page here, along with a new Nurgle Dreadnought too.