Changes

===Before the Coming of the Emperor===

====Pre-Reunification====

The only consistent information regarding Mortarion and his homeworld come from a single source: the ''Stygian Scrolls'' of Lackland Thorn, a historian and polymath attached to the explorator fleet that discovered [[Barbarus]].{{Fn|6b}}

===Great Crusade===

It was said that Mortarion brought his relentlessness to the Death Guard legion and they followed his ideals. He only ever found friendship in two other Primarchs, [[Night Haunter]] and [[Horus]]. He was actively shunned by [[Perturabo]] and [[Lion El'Jonson]]{{Fn|27}}. So close did Mortarion and Horus become that the ever watchful [[Roboute Guilliman]] of the [[Ultramarines]] and [[Corax]] of the [[Raven Guard]] approached the Emperor with concerns as to where Mortarion's loyalties lay. The Emperor waved it aside with a hand gesture; loyalty to Horus was loyalty to the Emperor{{Fn|1}}{{Fn|6b}}. Meanwhile, Mortarion was frequently critical of [[Magnus the Red]] over his use of [[Librarian]]s and was one of the chief voices to ban [[Psyker]]s among the Astartes Legions at the [[Council of Nikea]].{{Fn|11}} Mortarion expressed a hatred of all things related to the [[Warp]], and felt betrayed when he managed to sneak into the [[Imperial Palace]] and discovered the [[Golden Throne]] under construction. However after [[Malcador (Character)|Malcador]] explained that the purpose of the Golden Throne was to remove mankind's need of the Warp, Mortarion was put more at ease.{{Fn|10}} Mortarion also clashed with other Primarch's who he felt had upbringings far easier than his hell on Barbarus, particularly [[Sanguinius]], [[Jaghatai Khan]], and [[Fulgrim]].{{Fn|9}}

===The Heresy===

[[Horus]] found Mortarion more difficult to bring to his cause than either [[Angron]] or [[Fulgrim]], and for a time it seemed the Warmaster may have failed to convince the Lord of the Death Guard. However, Horus at last found a chink in Mortarion's armor; he was beginning to see the Emperor as having been corrupted with power and now was just another tyrant drunk with power. Indeed, Mortarion had become disgusted with what exactly the Emperor was, considering him a [[Warp]]-tainted "aberration" like his tyrant adopted father. Horus also used Mortarion's distrust of the Warp to his advantage, arguing that the Emperor had used the [[Warp]] in the creation of the Primarchs. Horus eventually used these doubts to bring Mortarion to his cause.{{Fn|6a}} Mortarion led his Legion in their betrayal of the Imperium at the [[Battle of Isstvan III]] and [[Drop Site Massacre]]. He later came to blows with [[Jaghatai Khan]] on [[Prospero]] after failing to convince him to join with them in rebellion. During the fight the two Primarchs were able to challenge the other, with the Great Khan proving faster and the Death Lord proving more durable.{{Fn|9}} Following the battle, Mortarion abandoned his pursuit of the White Scars and instead began a spiteful purge of the systems surrounding [[Prospero]]. During the purge, Mortarion encountered a [[Daemon]] possessing the body of a woman and was forced to kill it using his innate [[Psyker|psychic]] abilities despite it being against Imperial (and by this point, his very own) dogma. Realizing that the Emperor had lied to him about the [[Warp|Empyrean]], Mortarion vowed to master it.{{Fn|10}}

====Fall of the Death Guard====

After these campaigns, Mortarion received orders from Horus to make for Terra. Mortarion rejoined the primary Death Guard fleet under [[Calas Typhon]], who was battled the [[Dark Angels]] fleet in a campaign of misdirection in the aftermath of the [[Battle of Perditus]].{{Fn|12}} On [[Ynyx]] Mortarion and Typhon reunited, and their whole fleet set course of [[Terra]] for the [[Siege of Terra|coming battle]]. Upon Typhon's advice, Mortarion would make the journey inside the ''[[Terminus Est]]'' as opposed to the ''[[Endurance]]''. However, Mortarion found his once-beloved son Typhon changed, and once their vessels were inside the [[Warp]] the First Captain framed all of the fleet's [[Navigator]]s. Accusing them of agents of [[Malcador (Character)|Malcador]], Typhon had his [[Grave Warden]]s execute all of the Navigators but assured Mortarion that he and his [[Librarian|trained specialists]] could navigate the Warp to Terra. Mortarion's distrust of Typhon intensified as the Death Guard became afflicted with the [[Destroyer Hive]]. This plague transformed the Death Guard into bloated mutants, unable to die by any means. No cure was found, and it seemed the Death Guard was doomed to something as petty as disease. After Mortarion himself became infected, he confronted Typhon aboard the Navigator's station on the ''Terminus Est''.{{Fn|17b}}