Befriending A Demonic "CHARActer" ( A Female Chara x male reader )

So one day, on your way home, you saved a girl, then the girl asked you to escort her home. After that you had a little "happy accident" with her sister. And then, the story begin... ( A/n : " Also there will be a lot of grammar mistakes in this book and I will be very glad if you guy help pointing it out for me 😉 ) ...