Dazai had gotten rid of Mori to take his place, it took him a while to try to kill him but he would have succeeded. The Port Mafia did not agree with Dazai being the new boss. Dazai was in his new Office looking for some documents that prove that Mori left the Mafia to him. At that moment Chuuya, who is Dazai's partner when it comes to crime, arrived from the trip he had without understanding anything of what was happening, he was going to go ask Mori about what was happening