Im uncertain as to the current rules, but as far as I understand it players are allowed to have certain allies in their armies. For example, a Space Marine army could have Imperial Guard Griffons or Basalisks in their army, and count them as allies. But a Space Marine army couldnt however have a Tyranid Lictor as an ally.
Anyway, if you have a Grey Knights army, why not just include an ordinary Emperors Champion and class him as an ally model, from another Space Marine Chapter? That should work unless there is some sort of special Grey Knights rule that forbids it.
Similarly, Battle Sister armies lack a major assault force, so why dont they just throw in an Emperors Champion as an ally? That is still allowed isnt it?
A forum community dedicated to Wargamers, Wargaming 40K enthusiasts. Come join the discussion about Warhammer and Wargaming collections, miniatures, tactics, terrain, reviews, accessories, history, displays, models, styles, scales, reviews, accessories, classifieds, and more!