Let your wins cascade.
We’ve seen Beast’s “mystery ongoing power” when Muna used it, several times, during chapter 4; now of course it’s far less mysterious, we’ve already shown you Beast’s full profile. Here’s that power, pasted:
Inner Beast (warrior’s gift, Ongoing, -2). Self only. You channel your inner beast and gain the Brawler and Frenzy Edges. With a raise, you get Bruiser and Improved Frenzy instead. While active, you communicate mostly through angry growls. This power remains active for 2 rounds after it’s dropped for any reason.
In other words, you get pretty nice bonuses for melee attack and damage. It’s far from Mac’s strongest aspect, but you’ll recall that it’s difficult to damage Ivan from a distance.