jeffersonian000 wrote:It's debatable on if you can use units outside of the
IA codex to fill detachments in the
IA codex. This is something that should be clarified between players or by your
TO.
SJ
I don't remember any huge debate sweeping the forum, though it never hurts to ask your opponent/ally/
TO.
Just looking at the language of the detachment, I'd say
RAW you can take anything from Codex: Grey Knights since it's specified as a Grey Knight formation and only requires 1 Troop OR 1 Fast Attack and (not mandatory) a Heavy Support. I could see there being a
RAI argument that it should be limited to C:
IA, though I would be on the opposite side.