void blade

equip {2}
equipped creature gets +1/+1.
any creature that the equipped creature damages
but does not kill is exiled at the end of the turn,
it comes back from exile on its controllers next
upkeep step and gets a -1/-1 counter.
whenever this artifact puts a -1/-1 counter on a
creature the equipped creature gets a +1/+1
counter.
any enemy killed by the equipped creature is
exiled.