Ezekyle Abaddon is the former First Captain to the Luna Wolves. He revered his Primarch Horus as a father, placing him above the Emperor of Man. He was a part of the Mournival. Horus' council of four Luna Wolf Captain's (Garviel Loken, 'Little' Horus Aximand, Tarik Torgaddon, and of course Ezekyle Abaddon.) They served as advisors, each embodying different traits to present Horus with different options to any military or political situation. After the fall of Horus, Abaddon took control of the 'Sons of Horus'(Horus renamed them at the end of the Great Crusade.) and renamed them the 'Black Legion', desiring to expunge Horus' name from his Legion. Abaddon then continued to terrorize the Imperium, gaining the favor of Chaos Undivided, and is now arguably the Imperium's most dangerous foe.