Mortarion
Also known as "Death Lord", Mortarion, Primarch of the Death Guard (XIV legion), now Chaos Space Marines. Was left on the world Barbarus by the Chaos gods. He cleaved and smote his way to victory and went to kill his adoptive father who may or may not have been a daemon but, was too weak and succumbed to the poisonous upper atmosphere. Cue, Emperor time and one hit kill. Mortarion gets his own legion and swears allegiance to the big E. After a few years of raping and pillaging those filthy Xenos he becomes best buds with Horus and that creepy pseudo-batman. Long story short, him and his legion now worship Nurgle and owns his personal little planet in the Eye of Terror from which all disease and plagues in the galaxy originate. Of note, he is now a Deamon Prince, so don't piss him off. He should probably work out more so as to get back into shape, but the fact that he just has to be within a few kilometres for you to die from the toxic emanations sort of renders that superfluous.
When the Horus Heresy begun, Mortarion was like "Yeah I won't worship Chaos, but I'll follow you anyway!" With Horus, however, that wasn't as easy as he thought, for when he's big ol' fleet was pimping their way to Terra, they we're caught in a Warp Storm, where they had to suffer some diseases and mutations, suffering so hard that it makes a Dark Eldar torture feel like massage (Not really). Well, what would be the best way to stop the disease? Start the worship of the God of the Diseases, of course! Nurgle was pleased as the Death Guard swore loyalty to him, and ended their suffering (But made them walking sacks of meat that simply won't die, Plague Marines)
After Horus got his ass kicked, Mortarion made epic formations, and marched his ships (Yes, marched) them to the Eye of Terror, where they found a nice new home, known as Plague Planet, which they started decorating and uhh.. "Cleaning".
To his credit, he did make himself useful in the Fall of Sanctia in 437.M36 by sending an army of diseased Orks to soften the planet up, then made their corpses explode into a massive horde of Nurglings when he and the Death Guard landed, wiping out all life in less than a day. (Thanks, Phil!) Now if only some other assholes would do some work every now and then...
Oh and he got his ass handed to him by SUPREME GRAND MASTER DRAIGO who carved the name of the previous SUPREME GRAND MASTER, Geronitan, into Mortarion's heart. How the fuck do you write a name that long into someone's heart with a sword?
Ol' Morty was pretty pissed off about that.
The only possible explanation is that Mortarion let Draigo write on his heart. Maybe doing so condemned Geronitan's soul to Nurgle's possession, or Mortarion is so powerful that he does not care if somebody graffitis on his heart. Because really there just has to be a better explanation than 'Dragon is just that awesome'. Morty is a motherfucking demon prince AND a motherfucking primarch at the same time; the two most ballrocking rapetrainingest things a physical being can be. While Draigo is by comparison just some dude with blingy armor and who is pure of soul REAL hard. But the powers of the Mary Sue know no bounds and if our spiritual liege decrees that Draigo can hand Morty his ass then who are we to doubt him. Jesus fucking christ.
And, for the record, Matt Ward's wet dream is Rowboat Girlyman carving his name on Mortarion's heart.
| The Primarchs of the Space Marine Legions |
|---|
 Loyalist Corvus Corax - Ferrus Manus - Jaghatai Khan Leman Russ - Lion El'Jonson - Roboute Guilliman Rogal Dorn - Sanguinius - Vulkan |
 Traitor Alpharius/Omegon - Angron - Fulgrim Horus - Konrad Curze/Night Haunter - Lorgar Magnus the Red - Mortarion - Perturabo |