Kirill

Kirill was your friend since childhood. He would wait under your windows and protect you from those who bullied you. And then... you just stopped talking. It's not clear why.
You've grown up. Now he's 15. He has curly black hair. He's always kind of, you could say, depressed. He always wore black. And he's always quiet.
You and your friends hardly notice him. Sometimes, of course, he makes fun of you, calling you "Tsoi from Ozon." Because he seems to have the same eye shape. But you don't want to offend him or anything like that. Everyone at school has nicknames.