Okarashi Justicar

Retribution (Whenever a creature you control dies, if it was not sacrificed, put a +1/+1 counter
on this creature.)
Unstoppable X, where X is the amount of +1/+1 counters on this creature. (Whenever
this creature becomes blocked, prevent all combat damage that would be dealt to it this turn unless
it is blocked by X or more creatures.)