Kiara, the Void Breaker

Flying, Haste, Vigilance, Hexproof
Creatures you control have Haste.
Whenever Kiara attacks, Exile the top card of your library, until end of turn you may cast that card.
{w}{r}{u},{t}, Return Kiara to the command zone: Untap all creatures you control, after your next combat phase, there is an additional combat phase.