First Invasion of Osiris

The First Invasion of Osiris was an Imperial defensive campaign carried out by the Guardians of Osiris Space Marine Chapter against a large Chaos force comprised of several Chaos Warbands upon the Chapter's homeworld of Osiris.

History
The Invasion of Osiris was one of the most dire battles that the Chapter ever had. This invasion was made by a group four of Chaos Warbands commanded by none other then Anubis Kemet himself, going into the heart of Osiris territory to seek revenge. The battle on the planet was horrific for both sides. The Guardians of Osiris were bombarded by the Chaos ships and were then attacked by waves of Heretic Astartes and daemons. But after 3 months of bombardment, the ships of the heretics where attacked and destroyed by the Chapter's new flagship, the Pride of Osiris. With no more bombardments to destroy Osiris' fortifications, the Chapter regrouped itself and made a final assault on the enemy's territory, where Anubis Kemet was finally slain by the Chapter Master Ivar Freyson.