Sedna Campaign

The Sedna Campaign was an early campaign of the Great Crusade fought in 803.M30.

This campaign represented the final battle to liberate the outer regions of the Sol System from the grip of unknown aliens who had preyed upon humanity's home star system during the chaos of Old Night.

Eight entire Space Marine Legions were deployed against the xenos who controlled the "false world" of Sedna at the very outer reaches of the Sol System, beyond the orbit of Pluto. These legions were the Ist, IInd, IIIrd, Vth, XIVth, XVIIth, XXth and [REDACTED] Legions (later known as the Iron Revenants, Crimson Lions, Black Stars, Halcyon Wardens, Dune Serpents, Warriors of Peace, Alabaster Order).

The alien foe was destroyed by them through the use of unknown psychic means. In the aftermath, Sedna fell into silence and was lost to Imperial knowledge.