MArcomage

Text could be shorter. Like:
"Summon a card depending of matching card rarity (C - Imp, U - Nightmare, R - Daemon)".
BTW, idea is good.

Cute idea. I'd consider it a bit overpriced for the cost though. Magic lamp does more for the same price. Dwarven Watchtower (and to a lesser extent, Doppelganger) do about the same thing for cheaper.

Yeah my first thought was dwarven tower