Vecna, The First

Indestructible, Lifelink
As long as your marked cards in exile are less than
4, Vecna isn't a creature
At the beginning of your upkeep, put a marked counter on target creature.
Whenever a creature with a marked counter on it
dies, instead exile it with the marked counter.
You may play cards exiled with marked counters
and may spend mana as though it were any color
to cast those spells.