Kadthar, Dragoncaller

As long as Kadthar isn't paired with a dragon, he has "{t}: Search your library for a dragon creature card and exile it, then shuffle your library. Until end of turn, you may cast the exiled card, if you do, pair Kadthar with it."
As long as Kadthar is paired with a dragon creature, each of those creatures has flying and protection from nondragons and must attack or block together