Zven, Azorius Strategist

Every time you cast an instant or sorcery spell,
put one knowledge counter on Zven.
Remove two knowledge counters : Tap target creature, it doesn't untap during it's controller's
next untap step.
Remove three knowledge counters: Gain 1 life and
draw a card.
If you successfully counter a spell and you have
20 or more knowledge counters on Zven, you win
the game.