It's a long time since Black Library have released a graphic novel in their own right, having outsourced out to Boom! some years ago. GW's only title, the fondly remembered Warhammer Monthly ran from 1998 to 2008, being cancelled with many titles still mid story. Anyone who's read Daemonifuge, Malus Darkblade, or Bloodquest (and a range of other titles) has seen the fruits of these comics.
Sadly we've got a while to wait as the Black Library Blog states the release as November 2013 (Fingers crossed for a typo).
Here's what the blog has to say.
Written by Dan Abnett and illustrated by Neil Roberts, Macragge’s Honour will weigh in at a hefty one hundred pages. The full-colour graphic novel explores the epic naval battle that starts in Know No Fear when Kor Phaeron escapes in the Infidius Imperator and Chapter Master Marius Gage gives chase.
After the announcement, editor Christian Dunn held a short Q&A session. One of the questions was: ‘Will you go back and re-tell the Horus Heresy in this format?’
Christian said ‘no’ and went on to explain that while Macragge’s Honour would just be the first in a range of new Horus Heresy graphic novels, they would be focusing on telling new stories. Though he did drop some hints about revisiting key battles (specifically Prospero) and exploring different view-points on certain events. The names Gav Thorpe and Karl Richardson may also have been mentioned...
Initially, Macragge’s Honour will be released in a limited hardback edition, designed to match your other collector’s edition Horus Heresy books and limited edition novellas. As usual, this will be followed by a general release.
This all sounds very promising, as Dan Abnett is well know for his form on this sort of thing (*understatement*). Hopefully it'll pave the way for expansion into GW's other systems.