Ciatha, Fear Sovereign

Whenever a player casts their first spell each turn, that player mills cards equal to that spell's mana value.
Whenever a creature card is put into a graveyard from a player's library, you may pay X life, where X is its mana value. If you do, create a token copy of that creature, except it's a black Bird with flying in addition to its other colors and types. Then, exile all othe