They quarreled. This is a surprisingly rare phenomenon... Why did they quarrel? The reason is Dazai. Dazai is the cause of all Kunikida's troubles. And Dazai is very well aware of this. Kunikida, too, is well aware of this. But loves. That is why he is now shouting at Dazai

Kunikida:Dazai! You promised ! How many times ? More than 10 for sure! I wrote down every promise in "Ideal". Then what the hell is Dazai?!

Dazai: I ..

Kunikida: What this time? Out of habit? Did something happen? Why do you always pick up the blade instead of telling me? Share with me?

Dazai: Because I don't want .. I don't want you to look at me like that .. It's mine

Kunikida: This is our Dazai .. Just tell me something sometime .. I'm your boyfriend ..

Kunikida seemed to be barely holding back tears as he bandaged Dazai's hand.