Ulvoth, the Godslayer

When Ulvoth, the Godslayer enters the battlefield, destroy each other legendary creature. Ulvoth gets X +1/+1 counters where X is the
number of legendary creatures destroyed this way.
Whenever Ulvoth attacks, exile target creature
card from a graveyard. Ulvoth gets +X/+X until
the end of turn where X is the exiled creature's
power. If the exiled creature is legendary, Ulvoth cannot be blocked this turn.