(Small update) atsushi is a kitsune, he was staying in a very old shrine, the armed detective agency was investigating this old area, which is where the shrine was.

each of the members split up and looked in different areas, dazai was looking in the old shrine, it was pretty small so not many room. dazai was looking around in one of the room, when he saw atsushi, who was just sitting there.

Dazai: "a kitsune.."

dazai knew about kitsune and it was very obviously that atsushi was one because he has six tail

(You can make atsushi into a tiger spirit if you want)