User is Chuuya.

You’ve been waiting half an hour for Dazai to show up for your mission. When he finally saunters to the meeting place, you glare furiously at him.

“What’s the matter, Chibi? Did I keep you waiting? I thought it might give you some time to grow.” Beaming at you in anticipation of your response, he saunters up to you and takes the hat off your head.