Nazaliax, elder demon

: Black Creatures you control have "Tap 3 black creatures you control: put a loyalty counter on Nazaliax, elder demon."
-2: Put an emblem onto the battlefield with "Black spells you cast cost 1 less to cast"
-7: Each opponent searches their library and exiles cards so they only have one card of each type in their library. (Artifact, creature, Land Ect.)