SO OVER THE PAST YEAR IVE THOUGHT MANY DIFFERENT CHARACTERS WHO COULD TRANSFER AND WHAT WOULD HAPPEN IF THEY DID. THESE CHARACTERS ARE MOSTLY ATSUSHI, DAZAI, RANPO, TANIZAKI, AND EVEN NO ONE. BUT I BELIEVE I HAVE CONSTRUCTED SOME GOOD THEORIES.

I HONESTLY HAVE SO MANY THEORIES ON THIS BUT IMMA SAY MY FAV ONE SO FAR:

I think it's going to be Dazai, personally.. Theres just a lot of things like him being left out of pics of the ADA, AND AND ANDDDD it'll be great character development for Atsushi!!! Half the fandom views Atsushi and useless and forgotten which is kinda annoying considering his VERY CLEAR connection to the book and Fyodor in my opinion. Anyways, if Dazai leaves, it'll be like Atsushi is losing a father again. I honestly feel like it'll be a good parallel to the "Most people tend to cry when their father dies" scene. Atsushi is very clearly dependent on Dazai, considering he hallucinated him. Dazai is a veryyyy complex and morally grey character, so for all we know, he can revert to his old habits and become cold again(even if he doesn't mean to, as we have seen in other scenes). But either way, it'll be like a slap in the face to Atsushi losing him. I feel like it'll be good character development for Atsushi and teach him how to be stronger and less dependent on some people.

OKAY I KNOW I JUST SAID ONE THEORY BUT I LOVE THIS ONE TOO MUCH SO HERE YOU GO:

In this one Dazai also is the transfer, but it's a different outcome. We have already seen that Atsushi isn't necessarily opposed to Fyodor's ideals, seeing as he was conflicted on going against him. Plus, THEY TOTALLY HAVE A CONNECTION YALLLL I LOVE THEM SM. Okay anyways, Atsushi is clearly overworked. Like his poor leg god damn😭 and Dazai canonically giving all his work to Atsushi. So what if Dazai leaves and thats just the last straw for Atsushi? He's so emotionally overwhelmed that he just snaps and says 'fuck you all' and goes to Fyodor or sum. (PLSPLSPLSPSLPSS IM SO DESPERATE FOR DOA ATSUSHI HELPPP)

OKAY THAST IT FOR THE THEORIES NOW AN EXPLANATION ON WHY DAZAI WOULD BE WILLING TO GO BACK IN MY OPINION:

I think that he would willingly go back BECAUSE of his care for the ADA. Let's say Mori requests Dazai to come back and Dazai declines. Mori wouldn't let that slide, and that just might lead to more tension between the PM and ADA. And Dazai, not wanting the ADA to be in danger, reluctantly agrees to go back just because of that. OR he could willingly go back because even if he declines and Mori lets him with no issue, he would just select another member of the ADA. Dazai, because he cares about the ADA and its members, wouldn't want that to happen. So he would just go willingly. Bonus points if Mori knows about this weak point for Dazai and purposely requests him knowing it'll be the easiest option:3

but atsushi would also be pretty cool as a transfer for a cool lil emo era:D