Yeah, a cut scene where you lose control for a bit would probably be the easiest, and if they were going to do it it would be that.

You might be able to do some single player duty where you're stuck in your head? Outside your body is rampaging, but internally you're fighting some manifestation of the inner beast to get out (maybe a stretch, but fantasy RPGs do stuff like that, so idk?).

Or perhaps one of those switched roles they started doing in SB where you're playing as Curious Gorge and have to beat down the WoL.

The only other thing I can think of is a duty where the objectives are to attack literally everybody possibly including innocents until you're able to calm down or somebody else knocks you out. Which, while lore appropriate...might be a little dark to play.

Idk if anything feels good gameplay wise, so cut scene would probably be the way to go if they were gonna do it. I'd be fine with that tbh, since it's better than we what we have now; currently WoL basically starts being in control, meanwhile every other warrior struggles with it. :/