It strikes me as simply bettter writing, or at least, better fanfiction writing, if this new, extremely skilled and competent and apparently original character, can be explained by the original divergence between HPMoR and canon, and the most obvious way for that to be the case is if Voldemort controlled or impersonated him in some way, making his competence a consequence of Voldemort’s competence.
It strikes me as simply bettter writing, or at least, better fanfiction writing, if this new, extremely skilled and competent and apparently original character, can be explained by the original divergence between HPMoR and canon, and the most obvious way for that to be the case is if Voldemort controlled or impersonated him in some way, making his competence a consequence of Voldemort’s competence.