i play Khorne and i was thinking that i could give my Mighty Lord of Khorne the Mark of the Destroyer artifact and the Gorecleaver weapon artifact to make him double attacks, and extra rend on his Reality Splitting Axe. tell me if you think this is valid, because i play tested him against a Ahbborant Ghoul King on Zombie Dragon and he did 8 wounds and then i rolled a 5+ to shove it through the portal into the Realm of Khorne!!! MUHAHAHAHA!!! I love that ability! lol.
if the double attacks seems way overpowered, just know that if he fails to kill a model then he turns into a spawn and he would also have the Slaughterborn command trait to let him re-roll all failed hit rolls.
Core book, page 242. Edit: also in the core rules, page 15 (near the end). You can view them in the app as well.