Reyi, Sentinel of Dawn

Eminence — At the beginning of your upkeep,
you may pay {w/b}{w/b}. If you do, night becomes day.
If it's already day, you draw a card instead.
Flying
When Reyi, Sentinel of Dawn enters the
battlefield if it's neither day nor night, it becomes
day. Whenever night becomes day, return
target Angel from your graveyard to your hand.