The Images Are Taken From The BSD Wiki!^^ - Blog Posts

I think the most solid thing I could find was Akutagawa's wiki, specifically on the section on Dazai — which states that he was taken in at 14 in The Heartless Cur?

Also, during the anime adaptation his outfit looks closer to what he wore during 14-15, which is the coat hanging over his shoulders but drooping down in front of him?^^

Age 16, during the Dragon Head Conflict, he was wearing a two piece suit, I think?

So I think 16 as the age Dazai took in Akutagawa is canon?^^ Of course, I might be wrong!^^

I've recently seen multiple people say that in the Heartless Cur Akutagawa was 14 and Dazai 16, but is there any source to that? I thought the timeframe was never explicitated, but of course I might be missing something.

All the elements that I can think of that we know for sure are:

It must have happened before they were 16/18 (their ages during Dark Era)

It must have happened after Stormbringer; in The Heartless Cur Dazai says that that same day he was promoted to executive, which is something (timeskips aside) he wasn't for the entirety of sb (correct me if I'm wrong).

Same as above, it must have happened after the Dragon's Head Conflict because I *think* Dazai still wasn't an executive back then (I may be wrong. I know nothing of the dhc).

I guess it all boils down to how old Dazai was when he was promoted executive, but I don't think that was ever stated, not even in Dark Era... ?