Rev, Tithe Extractor

You may look at and cast cards exiled face down with Rev's last ability even if Rev leaves the battlefield. If another player gains control of Rev, that player can't look at or cast the cards you exiled with its last ability, and you still can.

An effect that instructs you to "cast" a card doesn't allow you to play lands.

You pay all costs and follow all timing rules for spells cast with the permission granted by Rev's last ability. For example, if the exiled card is a sorcery, you may cast it only during your main phase while the stack is empty.

If you leave the game, cards exiled face down with Rev's last ability remain exiled face down indefinitely. No player may look at them.