Edit: I figured that this makes too much sense with faeries. Since the spell countering ability is a mage ability rather than of the creatures she controls, I figure I'll rework this as a Faerie Queen.
Faerie Queen
Channeling: 8
Health: 36
Training: Arcane/Nature; pays triple for War spells
Abilities:
Quick Summoning: Can summon a level 1 Faerie creature as a quick action
Arcane Power: During the upkeep, gain 1 mana for each Faerie creature you control. Mana gained this way can only be used to cast or reveal metamagic spells. Any of this mana that is not spent during the round that it is gained is subtracted from your mana pool at the end of the round.
Noble Sacrifice: Sacrifice a faerie creature you control to cast a metamagic spell within 0-1 range of that faerie.
I'm thinking some Faeries will be limited in what kinds of spells they can counter with the noble sacrifice ability.
Thoughts?