Rhys, Stalker in Shadow

Whenever another Elf you control dies, put a +1/+1 counter on Rhys and you gain 1 life.

{b}, sacrifice an Elf: Rhys gains Hexproof until end
of turn.

Aurora {3}{g}{w} (You may cast this spell for its
aurora cost. When you do it becomes day if it is
night, otherwise it becomes night.)

Daybound