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 the infamous short story The Last Church.
Differences between Matt Ward And Graham McNeil's Ultramarine Work
 | 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. |
Like our spiritual liege Matt Ward, Graham McNeill is a fan of the Ultramarines. While you would expect that this would be fail, McNeill's writting not only makes it tolerable, but down right awesome. What makes McNeill a better writer than Ward is a simple overriding principle: Graham McNeill was not told by his boss to write the Ultramarines as flawless Mary Sues. In fact, Uriel Ventris, the protagonist of McNeill's Ultramarines series, has Uriel screw up massively in every book. His first campaign as a Captain saw Uriel release the Nightbringer on the galaxy, which had fans assuming that the Ultramarines had just damned the entire galaxy to a slow, agonizing death. The revelation that the C'tan are now shards limits this somewhat, but Ventris still probably doomed most of the Ultima Segmentum to a horrible death. His subsequent actions aren't much better, what with stirring up a hornet's nest on Medrengard, causing the ghosts of victims of an Imperial Guard massacre to gain enough strength to possess mutants he brought to the planet and kill those responsible, and bringing down the wrath of the Iron Warriors on Ultramar.
Even then, Uriel is not the only flawed Ultramarine. Cato Sicarius, the great and vaunted Captain of the Second Company, is portrayed as a borderline megalomaniac who is more interested in taking risks to become Chapter Master than for the Chapter. Perhaps the biggest shocker is that Marneus Calgar, everyone's favorite Mary Sue, actually lied to the Ultramarines about killing M'kar in 935.M41, instead binding him to the star fort Indomitable and claiming to "tear him limb from limb" as propaganda (with the implication being that all subsequent appearances by M'kar being equal propaganda)
Throughout the series, Graham McNeill explores how adherence to the Codex Astartes can be both a benefit and a drawback. After the battle for Tarsis Ultra, Uriel is charged with violating the Codex and put on trial. First Captain Severus Agemman visits Uriel and explains to him that ultimately, the Codex isn't about being a good soldier, it's about how to be a loyal Space Marine. This makes a ton of sense in hindsight, as the Imperium of Man has routinely shown that it holds independent thinking as the first step on the road to Chaos. By the end of the series, the rest of the Ultramarines are starting to realize that blindly following the Codex is costing them in the war with M'kar and Honsou.
Yet McNeill doesn't show the Ultramarines as completely flawed, either. Throughout the series, McNeill strives to emphasis that Uriel and the Ultramarines actually give a crap about the common people of the Imperium. At the same time, McNeill gives credit where it's due to other Imperial organizations, such as having the Raven Guard be able to sneak inside a Capitolis Imperialis vehicle, and even surprise Torias Telion simply be standing in the shadows. These things occur in The Chapter's Due, which is basically Black Library trying to repair the damage Codex: Space Marines did to the Ultramarines standing in the fandom.
One must wonder how Matt Ward feels about this humbling and shockingly human portrayal of the Ultramarines. It's likely he doesn't give a shit as he's already cashed the cheque he got for writing the codex. As Ward was instructed by GWHQ to ignore Black Library's output, Codex: Grey Knights ignores The Chapter's Due retcons about M'kar and instead inserts him into the creation of everyone's least favorite Mary Sue, Kaldor Draigo. At this point there is pretty much an undeclared war between McNeill and several other Black Library writers against Ward in trying to repair the Ultramarines image.
But we don't care. No fluff Matt writes is canon, because there is no such thing as canon in 40K.