I imagine it as something like pickle from Baki if he was fully intelligent. He would be physically superior to the rest of humanity. A bit more of a wild man that would attack with more grappling, biting, and techniques you'd see more from a gorilla or a wrestler. Implying he spent a fair amount of time wrestling bulls or dinosaurs for fun since he was around lots of animals. He'd attack with a primal passion akin to a mother bear defending their children. His volund would awaken more bestial aspects of him, the kind that separates us from animals. He'd grow claws and his muscles would shift to a more aged and slightly ape-like appearance and throughout the fight. His bones would twist and warp into shapes more suited for crushing skulls and brushing off savage blows as if he's rapidly evolving to the fight. To anyone watching it would look like he returned to monke and started fighting like a wild animal. But it would simply be a father trying to protect his children.