Sariel, Angel of the Moon

Soulbond (You may pair this creature with another unpaired creature when either enters the battlefield. They remain paired for as long as you control both of them.)
As long as Sariel is paired with another creature, both creatures have indestructible.
At the beginning of your upkeep, you may sacrifice a creature. If you do, return Sariel from your graveyard or exile to your hand.