10th Black Crusade
|Black Crusades of Abaddon the Despoiler||1st - 2nd - 3rd - 4th - 5th - 6th - 7th - 8th - 9th - 10th - 11th - 12th - 13th|
|Black Legion battles the Iron Hands|
|Imperium||Forces of Chaos|
|Unknown|| Abaddon the Despoiler|
| Imperial Guard
| Black Legion|
The Tenth Black Crusade, or the Conflict of Helica, was one of the Black Crusades of Abaddon the Despoiler, launched against the Imperium in 001.M39.[Needs Citation] Abaddon and the Iron Warriors ravaged the worlds of the Medusa system.
In the Tenth Black Crusade Abaddon forged an alliance between the Black Legion and the Iron Warriors, making a deal with their Daemon Primarch Perturabo. In exchange for Abaddon agreeing to settle a debt of vengeance against the Iron Hands, Perturabo opened an ancient Warp route out of the Eye of Terror for the Despoiler's fleet. The passage, calculated over several agonising months by the tortured machine spirits of a chain of enslaved cogitators, allowed Abaddon's forces to steal past the layered defences of the Cadian Gate and into the Helica Sector, spin ward of the Eye of Terror.
Once again, Abaddon employed a feint, sending the Black Legion fleet against Thracian Primaris, the capital world of Helica, while he attacked elsewhere. Abaddon also scattered his warlords across the sector and, on scores of planets, Traitor vessels thundered down from the skies to kill and maim Imperial citizens. While his warlords indulged themselves in the slaughter of Imperial worlds Abaddon traveled with the Iron Warriors to the Medusa System, home world of the Iron Hands. From the Vengeful Spirit he watched as the Iron Warriors laid siege to the loyalist Chapter. In a protracted war of attrition, the Iron Warriors systematically burnt the outer worlds of the Medusa System, tearing down the loyalist defences one by one.
Burning light of their ruined fortifications, the Iron Hands struggled to hold back the Traitors, buying time for their support companies to arrive. Before the bulk of Iron Hands and their allies could arrive, Abaddon and the Iron Warriors retreated, leaving hundreds of dead loyalist Space Marines in their wake. Though Medusa still stood, Abaddon had learned much about its defences and the Iron Hands themselves, both of which he would put to good use later.
- 1: Black Legion - A Codex: Chaos Space Marines Supplement, "The Conflict of Helica", pgs. 39-40
- 2: Liber Chaotica: Khorne, Black Crusades