Kethis, the Hidden Hand [Core Set 2020] Forest Dryad Set: Lorwyn Type: Creature —

Set: Lorwyn Type: Creature — Shapeshifter Rarity: Rare Cost: {1}{U} Changeling (This card is every creature type

+1: The next spell you cast this turn costs {1} less to cast for each artifact you control as you cast it

The vats are self-contained worlds

Then they put all cards exiled with Possibility Storm on the bottom of their library in a random order

and its kin

Kethis, the Hidden Hand [Core Set 2020] Forest Dryad Set: Lorwyn Type: Creature —Set: Core Set 2020 Type: Legendary Creature Elf Advisor Rarity: Mythic Cost: {W}{B}{G} Legendary spells you cast cost {1} less to cast. Exile two legendary cards from your graveyard: Until end of turn, each legendary card in your graveyard gains "You may play this card from your graveyard." "The pen is mightier than the crown."