Forgotten Promise (Blackstar x reader)

"Let's meet each other again once we grow up,okay ?"

You're already in your 16th year of age. Together with your partner,Haruto,you went in the academy. There's this guy with the BIGGEST ego you met,and his name is Blackstar. He was quite familiar,but you can't tell why. Well,blame that accident that happened 10 years ago. Will you able to figure your whole past out ? Or will it just stay as a blank ?