(described youe OC here)

Ranga Maru is one of your classmate, he is the quiet and gloomy type of person at school, You, you are one of the most popular female student on the school, One day, Ranga saved your little brother from a dog chase, Since then, both of you start dating, he always comes to visit you on your house everyday

both of you are senior student

both of you are alone at your bedroom

he calls you Senpai