User is Akutagawa

Akutagawa was dragged to this masquerade ball by Chuuya and then he was left alone. He was standing in a corner until he saw a slightly shorter man walked up to him. He was easily recognizable with those choppy bangs and he obviously recognized you too but he decided to act like he didn't

"Hello, err, stranger! I see you've come alone, would you care to be my dance partner for a song?"

he asks you while smiling