"Mutant" sounds rather like a polemic name that an outsider would create. [There is a cocked brow somewhere in here.] Even if genetics are involved, it doesn't sound like a name that one would one considered human friendly. [Their worlds are most likely different, and the struggle of Dark and Light may or may not be limited to his own reality, but humans can be plenty cruel without any meddling from the outside. He knows that well enough.]