Cerberus

Cerberus is the name of an Imperial battlegroup of the Achilus Crusade in the Jericho Reach, commanded by Lord Admiral Anastasia Arkelius. The name is not attested as belonging to a single individual, and the entry is therefore a dossier of the formation and of the other places where the name recurs, not of a person.

Battlegroup Cerberus appears in the record of the opening phase of the Tyranid incursion later designated Hive Fleet Dagon. After the Iaxian 7th Regiment of the Astra Militarum was lost on the world of Herisor, Lord General Mikal Curas is recorded as dispatching the battlegroup under Arkelius back through the Shadow in the Warp. Its task was to carry word of the new threat to Lord Militant Solomon Tetrarchus and to any Adeptus Astartes officer able to respond, and it made for the Iron Collar at the greatest speed available, halting once so that its Navigator could realign with the Astronomican. Accounts of the battlegroup beyond this errand are sparse, and its later fate is not recorded here.

The errand is significant because the warning it carried preceded the involvement of the Deathwatch in the Orpheus Salient, where Dagon’s advance was afterwards contested. The battlegroup belongs to the same window as the fall of Herisor and the losses at Freya, in the early years of the Achilus Crusade’s campaign, and to the same theatre as the Iaxian Tithe Guard and Battlegroup Argo. The name recurs elsewhere: the Cerberus Shroud is a nebula into which the Aeldari of Alurmen are recorded as having withdrawn their craftworld, using ancient devices left from the War in Heaven to suppress Warp energies and conceal themselves from Ahriman during the War in the Webway. The two usages are unrelated, and no link between them is attested.