MArcomage

With Mage deck you'll definitely have more magic than your opponent, and most of the times your magic will be significantly higher - +3 or +4 magic. I'm not sure that I want to give +3 magic to opponent for ~23-28 gems at best, to be honest.

Changed it. Attack 3N, steal N gems, N=#enemy magic.

Now I like it much more.

This new version is very likable, except there will rarely be cards in enemy hand with high enough cost to satisfy it's own cost.

But still gem costing persistent mage is nice

Maximum 80 damage? That's an amazing damage/cost ratio, especially on a persistent card, unlikely as it is to be matching something costing 30 gems. Except in a Hidden game, the opponent would be sure to discard whatever matching card has a high gem cost.

i missed the 2N part, oops

It's cost could be raised or max reduced to 20.

I wouldn't increase the cost. I figure that the opponent is likely to park a non-gems card across from it, so you have to make sure it's not terrible without the added effect.