Penn, the Half-Troll King

At the beginning of your postcombat main
phase, you may pay X life, where X is the
number of opponents that were dealt combat
damage this turn. If you do, fateseal X.
{1}, Sacrifice a creature: Put a +1/+1 counter on
target creature, it gains haste until end of turn.
Partner(You can have two commanders if both have partner.)