Keepers of the Core

Evict - Whenever a Rebel enters the battlefield
under your control, exile the top card of your
library. Until end of turn, you may play that card
if four or more cards you own are in exile.
"I have just discovered that there are those that dwell
in the heart of Everhaven. They have allowed us safe passage to the island, and for that I am eternally
grateful."
- Ordaniwen's journal, entry 8