Ori, Spirit of Nibel

Reach
When Ori, Spirit of Nibel enters the battlefield,
create a 1/1 white/blue/green "Sein" token. It has
Reach, Menace, and Indestructible. If Ori is
removed from the battlefield, sacrifice Sein.
Once during your turn, you may pay X, where X
is {3} + the number of Sein counters on Ori:
put a +1/+1 counter on Ori and Sein, and a Sein
counter on Ori. If Ori has three Sein counters,
Ori and Sein get Double Strike.