[Y/N] comes from an assassin family that has the ability to regenerate at a incredibly inhuman speed, and immunity to poisons and certain diseases. Just like a certain white-haired boy, she does not want to be an assassin. [Y/N] later comes across the Hunter Exam, and to get away from assassinations she takes up the challenge. She meets new people, and despite being an assassin she's pretty innocent. Gon x reader x Killua

A girl with galaxy eyes named Selina was taken as a little girl and was put through experiments that gave her inhuman abilities. She was saved at the age of nine by a white haired assassin.