It is thought that Kossolax was originally known as Solax, Sergeant of the World Eaters 3rd Assault Company, before the Horus Heresy. This theory is largely based on sightings of the Barbarus, a Rhino transporter which belonged to Solax's squad and was reportedly present during the Siege of the Imperial Palace at the height of the Heresy. Since then, the Barbarus has been spotted on numerous occasions throughout the millennia in service of Kossolax.
The First War for Armageddon
In 444.M41, Kossolax joined his Primarch, Angron, in the First War for Armageddon. At that time, Kossolax's veteran warriors had already proven themselves in eight campaigns against the Imperium of Man.[Needs Citation]
Though the forces of Khorne overwhelmed the planet and caused a bloodbath, their hold was ultimately broken. Angron and his Daemonic minions were banished and the warriors of Khorne repelled. During their withdrawal a part of the Foresworn warband was left back on Armageddon.
The 13th Black Crusade
Kossolax recently reappeared during the 13th Black Crusade of Abaddon the Despoiler. His forces invaded Agripinaa, where they were confronted by the Blood Angels led by the Sanguinary High Priest Numitor. In order to turn the tide of the battle, he ordered his berzerkers to fall upon their allied cultist hordes. The massacre that ensued was enough to summon a mighty Bloodthirster who dealt heavy losses to the Blood Angels and their Death Company. Although they managed to overcome the daemon and drive the World Eaters from the planet, Kossolax was not slain. Seeking vengeance, Numitor vowed that he would hunt him down, no matter the cost.
After the destruction of Cadia, Kossolax reappeared leading the Conqueror at the head of a large Chaos fleet that included World Eaters, Night Lords, Death Guard, Thousand Sons, and Black Legion to attack Agripinaa.
- 1: White Dwarf 275 (UK) - Index Astartes: Beasts of Steel - Chaos Space Marines tanks - The Rhino
- 2: Codex: Eye of Terror (3rd Edition), pg. 16
- 3: White Dwarf 286 (UK), pgs. 68-69 - Index Astartes: The Eye of the Storm - Blood Angels
- 4: Conquest of Armageddon (Novel), [Needs Citation]
- 5: The Lords of Silence (Novel), Chapter 14