Kusuha is all up in this. Not sure if she's Perceval or Galahad for purposes of "why are you so dumb/naive/overpowered", but she's in.

Also Signum might be a good international member of this but I don't want to have two characters in the same kingdom/faction.

And I think the way of implementing it is making the core ideal "group of honorable knights" rather than "the King(s) of Britain's personal asskickers who happen to be honorable knights".