Ojutai, Soul of Winter

Flying, vigilance
Whenever a Dragon you control attacks, tap target nonland permanent an opponent controls. That permanent doesn't untap during its controller's next untap step.

Dragonlord Ojutai

Flying
Dragonlord Ojutai has hexproof as long as it's untapped.
Whenever Dragonlord Ojutai deals combat damage to a player, look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.