It's one of the Clockwork dudes from "The Girl in the Fire Place." my favorite story from Season 2 of the new series. It's an interesting figure.
And a good interesting. It has limited articulation, no mid-thigh or bicep swivels, but that sort of works considering the robotic nature of the character. Unfortunately there's no mid-torso swivel either, and that would have been nice to see.
Accessory wise, that blade weapon in its arm can be removed. And even more interesting, that mask face is an actual mask. You can remove it to reveal the clockwork robot underneath.
And that's pretty fricking cool.