Hella, Xathrid's Emissary

Unleash, first strike, trample
Spells you cast cost {1} less to cast as long as each
of your opponents was dealt damage this turn.
Hellbent — Whenever Hella, Xathrid's Emissary
deals combat damage to a player exile the top
two cards of your library. For as long as those
cards are exiled, you may cast them.