She taught me how to love [Killua x reader]

"Dad, I tell you, I don't need a mentor!" Silva sighed, "Killua, have you seen your grades? I mean, you got a D in English, that's one of the easiest subject and yet you still failed." "Then I'll study harder!" "You've already said that like 5 times this month and you still haven't improve." "But Dad-" Killua was...