Treachery of Kuthru Zarlan

The Treacher of Kuthru Zarlan was one of the most lamentable events that occurred in the annals of the Blood Serpents Space Marine Chapter, when one of their own, High Chaplain Kuthru Zarlan, secretly conspired to corrupt his fellow battle-brothers to the worship of the Chaos Blood God, Khorne. The traitorous High Chaplain convinced the Chapter's fallen battle-brothers of the Death Company that their fellow warriors were, in actuality, had fallen into chaotic corruption and needed to be eradicated. This resulted in a small internecine conflict amongst the Blood Serpents, which ended with the death of the former High Chaplain.

History
Shortly after turning back the invasion of WAAAGH! Klawchrusha, High Chaplain Kuthru Zarlan gathered up the Blood Serpents' Death Company, telling the rest of the Chapter that he was preparing to kill them, as is Blood Angels' tradition. However, Kuthru had secretly fallen to Khorne took advantage of the high number of Death Company, and his role as leader of them to try and kill off the chapter, and create a new Cult to Khorne on Astoran.

Kuthru Zarlan convinced the Death Company that the Blood Serpents were the enemy, and turned them on their former brothers. The Death Company caught the Blood Serpents completely off guard, the initial strike wiped out what remained of the 5th company, which had suffered least from the Ork invitation. However, Kuthru's treachery would not be able to get much farther, as shortly before he died, Captain Ragos set off an alarm alerting the rest of the chapter.

Then the newly promoted Chapter Master Cronagg gathered what remained of his forces to bring down the treacherous Chaplain. The fight that followed was deadly to both sides, with all of Zarlans forces going down, but taking two loyalists for almost everyone of them. Culminating in a fight between Cronagg and Zarlan, while Zarlan never stood a chance in the fight, he did manage to severely wound Cronagg's left arm before being beheaded by Cronagg's axe.