Defense of Helioret
From Warhammer 40k - Lexicanum
The Defense of Helioret was a battle of the Great Crusade in 962.M30.
The insane Witch-Idols of the Eldar Craftworld Magc'Sithraal led a brutal campaign of raids against Helioret, forcing the Blood Angels and Ordo Sinister to defeat the Xenos and cast their Craftworld into a nearby star.
- 1: The Horus Heresy Book Eight pg. 16