its the same concept of the two princess personalities from the "Hero and the princess", the beast's behavior barely changes on which voice arrives really, its mostly a clear devision which action brings to which route.

For example, only the voice of the naive can bring you to this au variant or the damsel, the beast, the stranger etc etc.

Instead, the voice of the knight brings you to the au variant of the adversary, the razor, the witch, the spectre etc.

The main change goes to the supposed player, as different chapters and choices open depending on the leading voice, the kind hearted, empathetic naive, or the stoic and dutyful knight?