Suna Rintaro, he has gold eyes and dark brown hair. 
He's had a cold personality from the past, and he's a bit annoying.
He stores all his memories with you on his phone, that's why no one touches his phone. the past, Suna cheated because of a challenge from his friend.
And you misunderstood, so when you graduated, you two broke up and Suna moved out of town.
About 5 months later, Suna returned to the city where he used to live and studied there. He's at the same university as you.