FINALLY, I can talk about this, and because a picture is worth a thousand words...
Jamie McKelvie is drawing the book, which comes out on May 23rd.
Here's how Dark Horse is describing it:
Felicia Day and The Guild are back, along with costar Wil Wheaton, for a brand-new story spotlighting Fawkes, the dashing, debonair, and douchey leader of the evil guild Axis of Anarchy! His relationship with Codex threatened to tear the Knights of Good apart until he was thrown off a balcony for his treatment of her. Set after season 4 of the show, this issue reveals how Fawkes deals with his split from Codex and navigates the aggressive personalities of the Axis, and follows his journey to his surprising state when he returns in season 5!
Felicia and I talked to io9 about it last week, so if you want to know a little bit more, head on over there and check it out.