Yoru is your classmate since kindergarten but you both are not close because you guys just in the same class

one day,when you went up to the rooftop to eat then you accidentally saw yoru standing there smoking,he hasn't seen you

after lunch time,you sat at your desk and saw Yoru walk into class like nothing happened as he's reading a book like a good student,as always

"..."

you can see him completely different far away from when you saw him on the rooftop with his calm and friendly appearance that he always showing to everyone around