No me lo he inventado, viene en el Horus Heresy vol. II y en el vol. IV
Vol II. Snaguinius es mandado por Horus a limpiar el Signus Cluster, infestado por los demonios de Slaanesh de Kyriss. En medio de la refriega se encuentra con Ka'bandha, que viene a corromper a los sangrientos.
On the battlefield pf Signus, Sanguinius faced Ka'bandha, Greater Demon of Khorne [...]
-Why do you fight us, so-called Angel? You may be able to best me, but you cannot hope to defeat Chaos. My Lord Khorne is powerful beyond any means you can measure. [...]
-Begone, daemon! I wolud deal only with your master Kyriss, Be gone, or I shall cut you down.
-Kyriss is no master of mine, little angel. I answer only to Khorne [...] You are a creature of blood as much as I am. Join with me, join with Khorne! You can be his most exalted champion. [...]
-[...] There is nothing you can say that would entice me to cast aside my oath of loyalty to the Emperor. I will destroy you and all of your foul kin!
The fight was fierce and bloody, the carnage appalling [...] Sanguinius was momentarily unbalanced as his legs were crushed in the whip's coils. The daemon smashed him to the ground with the flat os his axe. [...]
-Come at me again, daemon! Feel the lick of my sword a second time if you dare!
Ka'bandha looked down on the smitten Primarch
- I let you live this time, manling. Your legs will heal but this wound will always fester. The winged Primarch had fought a bloody aerial duel with a mighty daemonic lord of Khorne [...] Sanguinius had dealt the creature a terrible wound and in response the greater daemon has crushed his legs, cast him to the ground and with a howl had slaughtered near five companies of the Blood Angels as it fled the scene. The trauma os this act of malevolence has stunned the Primarch into unconsciousness.
[...]Rather, they redoubled their efforts to banish the daemon horde. Filled with vengeful fury, the Legion fought as it had never fought before. The Blood Angels went Berserks and in their mania they smashed the daemons asunder.
[...] The brutal violence of the daemon Ka'bandha had unleashed something dark within the psyche of the Space Marines, a thirst for blood that would not be slaked until every taint of Chaos had been erased from the planet.
The Angel Sanguinius was a Space Marine Primarch [...] Within a few days the Angel was able to walk [...] As his legs grew stronger and the pain from them slowly subsided, he notice a change in his Blood Angels. [...] Whatever befell him in the future, he vowed to himself that he would have his vengance on the daemon Ka'bandha.
Sanguinius took up his position above the Ultimate Gate, the main entrance to the Imperial Palace. [...] The creature was tall, taller than any around it [...] The daemon flew towars Sanguinius and he recognised it instantly - irs name was Ka'bandha and he had fought the creature before.