The Scourge of Elros came as a result of the actions of the Daughters of El, a coven of assassins based on the matriarchal feudal world of Elros. Seven suicide bombers managed to inflict serious internal damage to several 10^th Host vessels and nearly succeeded in killing Apostle. After tracking the killers back to the planet Castor ordered the fleet to assault the planet, wanting to punish the offenders.

It turned out to be something of a trap. The Word Bearers captured the enemy’s primary stronghold and chastised them thoroughly; only to be attacked by hidden atomics. Only those Astartes in terminator armour – Castor included – had any chance of surviving the initial blast; and was teleported to safety from under a mountain (literally) of rubble.

Outraged Castor launched the entire 10^th Host and its attending God-Machines against the natives of Hilarion. While his troops were engaged in slaking their thirst of blood and vengeance Castor received an ominous warning form this Chaos Sorcerers: The arrival of a major Imperil fleet was imminent. Another trap! The Imperium seemed willing to sacrifice an entire world if only the 10^th was cornered and crushed.

Choosing to live to fight another day Castor ordered the nuclear obliteration of all remaining population centres, then pulled out and hauled ass out-system – in the nick of time, as two enemy squadrons number a total of 4 BCs, 6 CAs and 11 DDs (same squadron that came hunting for the 10^th as Ichovor) came howling out of the warp, ready to pounce upon the 10^th.