Fatpixel

Please excuse my ignorance. As I understand it, if I run Blades of Khorne with Khorne marked knights, or warriors the latter are not taken as Allies. However if I take a Slaves to Darkness army, even if they are all Khorne marked, a Bloodsecrator or Flesh Hounds I’d like to take from the BOK would be allies for not more than 20% of list. Just trying to look down the right end of the telescope here.