Thresh, the Chain Warden

Whenever a non-token creature you don't control
dies, exile it with a cage counter on it.
Thresh, the Chain Warden gets +1/+1 for each
card in exile with a cage counter on it.
At the beginning of combat on your turn, each opponent may sacrifice a creature. Creatures controlled by players who didn't get -X/-0 until
end of turn, where X is the number of cards in
exile with cage counters on them.