Broken by the death of Horus and sick of war, Abaddon wondered alone into the Eye of Terror. Get the full story right here!
Via our good friends at Lexicanum
After Horus’s recovery, Abaddon grew ever more protective of his Primarch and his Legion’s reputation. He saw remembrancer criticism and Imperial investigation into Legion activities as threats and insults that could not be borne. He therefore sanctioned the murder of Ignace Karkasy and the blaming of Legion-caused civilian casualties upon Garviel Loken. This course of action was frustrated by the refusal of Tarik Torgaddon to accede to the plan, and the Mournival brotherhood was effectively broken as a result.
Abaddon’s thinking would prove to be in tune with that of his commander, who would eventually order not only the death of Karkasy but also that of Loken. Seemingly destined to be in lockstep with the Warmaster, Horus came to the warrior-lodge of his Legion to sway them into following him onto what would prove to be the path of heresy, Abaddon was amongst the first to swear his unquestioning loyalty.
Abaddon was present at several of the major actions of the Horus Heresy. During the purging of the loyalist Legionaries at Isstvan III, Abaddon notably took to the field to attend the final meeting of what had once been the Mournival, at which he dueled with Garviel Loken. Though slightly wounded in the combat, Abaddon emerged the victor. Abaddon again dueled Loken on the Vengeful Spirit in the aftermath of the Battle of Molech after the Knights-Errant attempted to assassinate Horus.
He later appeared at the forefront of battles at Yarant, and in the Siege of the Imperial Palace. During the final confrontation, Abaddon fought against Terminators of the Imperial Fists Legion aboard Horus’s battle-barge, the Vengeful Spirit, and thus was not present when Horus was defeated by the Emperor. Abaddon’s anguish at the death of his “father”, drove him completely mad. Before the Sons of Horus retreated, Abaddon led a vicious counterattack that reclaimed the Warmaster’s body, before leading the retreat into the Eye of Terror.
