Arngeir, Scholar of the Voice

When Arngeir, Scholar of the Voice enter the battlefield, put a +1/+1 counter on it for each Greybeard creature on the battlefield.
When Arngeir, Scholar of the Voice
or another Greybeard creature is destroyed,
put an Instant — Thu'um spell from
your library to your hand. Shuffle your library
"Sky above, Voice within."
―Arngeir