Assault of Azurus Optima

The Assault of Azurus Optima was one of the most lamentable events in the history of the Dragons Sanguine Space Marine Chapter, when they suffered extensive losses at the hands of a large raiding force of an unknown Kabal of vile Drukhari. The Chapter's home system was raided extensively by the foul xenos, including their fortress-monastery of Blood Fall. During the attack, the Chapter barely managed to rescue their relics and a small portion of their gene-seed before the destruction of their flagship. Despite pushing back the Drukhari raiders and driving them out of the system, it would take several centuries before the Chapter was able to bring back the numbers of battle-brothers to full-strength.

History
In 355.M39, the Chapter suffered one of their most dire events in their history. The large raiding force of Drukhari came to pillage the Astartes home solar system. The local Astra Militarum regiments and Astartes barely managed to destroy half of the fleet before their ships started to drop like flies. Between those ships were the Chapter's Fortress-Monastery of Blood Fall. The Chapter only managed to rescue their valuable and irreplaceable relics and 15% of their precious gene-seed from the genetic gene-stores, and get them aboard one of their battle barges before the ship exploded, taking with it two other small Drukhari battleships. In the end, the Chapter managed to eliminate 95% of the raiders before the attackers fled back into the warp. Bereft of vital gene-seed, this left the Chapter severely mangled and barely able to create more battle-brothers for the Chapter.