Graham McNeill
A writer for the Black Library.
Not Dan Abnett, but forms the Holy Trinity of Black Library writers with him and Sandy Mitchell, (Which makes ADB the holy child or something)
Wrote the Ultramarines novels and some Iron Warriors shit. When he's writing them, the Ultramarines are not just tolerable but actually awesome.
He's also written several Horus Heresy books, including A Thousand Sons, the first Black Library book to hit the New York Times Bestseller list, the infamous short story The Last Church. On the other hand, he did write The Reflection Crack'd, which had Fabius Bile rape Fulgrim with an iron rod. So fail there. Oh, and Codex: Black Templars.
He also wrote the Time of Legend: Sigmar novels, the third novel of which gives a brief preview of the origin story of Morkar the Uniter. Very nice Mr McNeill, now write that story.
McNeill's writing style is very 'tell, don't show.' His books tend to have characters deliver their lines in uninterrupted chunks with minimal indication of what's going on around them, and very flat emotional inflection in dialogue.
On the other hand, his stories have a wealth of background information and detail, and his few character driven stories are very good as well (read Priests of Mars).
Differences with Matt Ward
 | This article or section involves Matthew Ward, Spiritual Liege, who is universally-reviled on /tg/. Because this article or section covers Ward's copious amounts of derp and rage, fans of the 40K series are advised that if they proceed onward, they will see fluff and crunch violation of a level rarely seen. |
He's taller and has less hair than Ward. Also, he wrote the Ultramarines from the perspective of a novelist writer above the third-grade level, so they're not simply Mary Sues. Ward's inability to stop jerking off over the Smurfs leads him to depict them as caricatures of themselves that can do no wrong, whereas McNeil is a more competent writer who's willing to let the Ultramarines have flaws without making them look like absolute failures.
That said he's far from being universally liked. Some Ultramarines fans view him as going too far in the other way. Making them total failures and a vibe of "Cool Smurfs don't follow the Codex".