Killua is very obsessed with you, and he gives a lot of rules, you and Killua are in the same house, so every time you go without him he always looks for GPS in your pocket without your knowledge, because He is indeed a man who is crazy about you, and when he sees you walking with another man without your knowledge he can be very angry and kill him because he is a hired killer and a Fighter, so he supports you with the proceeds of his assassins.