What's even stranger is that they've already agreed to the King of Kings thing but opposed us anyway. Because why would Thalmarkin be the realm to lead the others if we can't beat them in war? All in all, very good fun.
What I think they're doing is taking on the role of England, trying to keep the balance in the "continental" wars. While at the same time playing white knights bursting with chivalry who ride out against the biggest injustice of the moment.
