mtg cards cannot be exiled Rules Text: exile, library, can't, 38 cards Do I have to pay

Well also want to put in a bunch of cheap creatures with power two or greater that wed be willing to sacrifice to the casualty ability

If you can defend this Dimir planeswalker , you should be able to exile opposing graveyards three or four times, making it hard to build a full graveyard

Any activated effect goes infinite with the staff so long as you have a free sacrifice outlet like Ashnod's Altar

Being able to draw upwards of three cards in a turn at the expense of just three life means you will have plenty of opportunity to draw into some extra removal or combo pieces very quickly

Not to be outshone by Kefka, Kefkas Tower returns to us as Bolass Citadel