I think a couple chapters ago she mentioned it when MC was curious.
Nanomachines?
She was raised by an alien, so perhaps she's a human orphan that was augmented somehow or taught something special. Her comment of retaining something in her 'anima' makes me wonder if she has like... I dunno, special Alien martial arts to enhance her body, like Chi sort of stuff.
That being said... It might be a translation thing but she described herself as an '
Earthling', so she could still be non-human. An alien born and raised on Earth would still be an 'earthling', after all.