>>39551444Wuji is closer to the original dragon, something primordial and supreme, but lacking in distinction like yin and yang/Reshiram, Zekrom, Kyurem. It wouldn't be wuji if there's polarity, which describes normal Kyurem, but not Kyurem's forms.
These forms aren't the supreme dragon, the supreme dragon isn't coming back much like the primordial, supreme wuji. Instead, we got forms that are a new creation with distinct, distinguishable elements, something made after polarity was established.
Kyurem getting stronger in a new way parallels the story told in BW of the line being drawn between man and pokemon, the two coexisting, and the bond between the two creating something strong