Smut aside, the white haired monster must be the Crown Prince while the red/brown haired one was his Knight? And the current Emperor might be the Crown Prince's brother or relative and he made them a monster so he can take over the throne?
Smut aside, the white haired monster must be the Crown Prince while the red/brown haired one was his Knight? And the current Emperor might be the Crown Prince's brother or relative and he made them a monster so he can take over the throne?