Kyriss

Kyriss the Perverse was a Keeper of Secrets. Along with Ka'bandha, he was one of the two daemonic "generals" who orchestrated the Battle of Signus Prime against the Blood Angels and their primarch, Sanguinius.[1a] Horus and Ka'Bandha however intended to use Kyriss as a "sacrifice" to drive Sanguinius into a rage and eventually turn him to Khorne. After Ka'Bandha was forced back into the Warp, Kyriss informed Sanguinius that he would spare the Blood Angels of the Red Thirst and Black Rage if he took the hate of one of his lost sons into him and stepped into the realm of Chaos, but to save his gene-father the Apothecary Meros did instead. In a rage over the fate of his son, Sanguinius decapitated Kyriss