Whenever you cast a spell you don't own, create a 3/3 black Demon creature token.

+1: Draw a card. For each opponent, exile up to one target instant or sorcery card from that player's graveyard and put a page counter on it.

−3: You may cast a spell from among cards in exile with page counters on them without paying its mana cost.

Tasha, the Witch Queen can be your commander.

Each opponent exiles cards from the top of their library until that player has exiled cards with total mana value 20 or more.