Losing Chuuya
Chunya is a caring character, and so other's reaction to his care is either going with or without, as it either might help them or bring them more problems.
This is reflected in his power, he's so unable to control it; that yes, it will help him wipe out all enemies, but in an instant he's flipped against everyone else including those he cares about.
He feels that Dazai's betrayal to the Port Mafia is a personal one as well, it wasn't only a simple moral move for Dazai to choose to be away frown the "bad" guys, and we start to see that after the initial story of BSD shifts from when the authors were presenting the lines of human morality between only back and white, however; the show goes on to try to explain that morality is much greier than it may look.
Although that some characters perceive morality in their own way, Dazai called Mori a pure ''evil'' for instance. Not to say that he has a black/white morality code, otherwise he'd not be involving Shin Sokuku together, so him calling Mori out is I think Dazai's unconscious defence mechanism against Mori's attempt to control Dazai's future, Mori wants Dazai to be the next Port Mafia boss, and this defence mechanism of villianising Mori to an extreme is Dazai's way to steer away from him at all costs.
This is where the writer loses Chuuya and what does his moral compass look like, which can be explained if Chunga is written to handle a case, where as insinuated in S3, where it seems gifted individuals can be artificially made, this would contribute much to the story since it sets itself to be an investigation of humanity.
Despite this, I don't think well get any more of Chunya besides being caring to the point of insane self sacrifice. because modern and even contemporary Japanese literature focuses on exploring the greatness of being human through the mundanity of life, Japanese literature is closer to Wordsworthian poetry while having to dive into the abstract nature of humans purely on abstract means is more in line with maybe French or Russian literature.
On his journey he might get to finally decide to forgive Dazai or not.
If you have anything to comment on regarding this analysis or how Chuuya's journy would look like, please tell me, I might be a little inspired to write a fanfic about this, or even co-write about Chuuya.
