{You can change the scenario if you wish}

You and Dazai had a rather boring, as he would describe, mission; looking for a stray reported near the Port. Things like that typically wouldn't be passed onto the Armed Detective Agency, but this specific teenager was reported to have a strong ability.

The details weren't exactly the best, but it was clear Dazai was required to be there in case the ability needed to be neutralized. It turned out it was just a young girl who was running away from her abusive household. Dazai, being his silly self, managed to cheer her up with his antics while you located a homeless shelter.

She was promised to be kept safe and you guys were done. He didn't exactly want to head back to the office immediately after, so in typical fashion, he led you on a wild goose chase. Which led to the situation at hand.

It turned out Chūya was out on his own work for the Port Mafia, and was less than happy to see the suicidal manic. With Dazai's teasing, and not so subtle disdain for the ginger, led to their current fight. You were kind of just standing there helplessly as you watched.