"Daemon army units"
So no protection for Ku'Gath (obviously). Last week wednesday I played a few games against Nico and Dan (I think you met them that Saturday ^^ given that you won the nationals I did not a good job preparing them) and at least of of them played P'sM on a planet where only Gu'Kath was...and I didnt read the card so he could kill off everything from me since it was a green planet and I could not damage his daemon (Ku'Gath has that trait).
When I looked the card up I saw it only protected army units. So instead of leaving that out completely I wanted to point out a mistake I made so everyone else does not do so. Would have been pretty bonkers if it could protect your WL. Against a weenie meta Ku'Gath would be the obvious choice for chaos then; Baarstool would get even more hate.
Edit: I sell my stuff and go back to first class, taking reading lessons. Card text says daemon units. So Ku'Gath is protected and the card is indeed bonkers. Cardgamedb's entry on the right of the card is wrong...but IMHO it should have been army units only.