Of Osamu and Alice

Dazai is the only connection Alice has to her past within the ADA.

After being found by him and Kunikida in an alleyway and bringing her to a hospital to be treated, Dazai asks Fukuzawa if she could be put through an entrance exam and permitted to join after she wakes up amnesic. Dazai explains very briefly to Alice that she may not remember, but he did know her in the past and would be willing to help her regain her footing as a member of society and keep away from the Port Mafia. With no other options and nowhere to go, she accepts his offer. 

Dazai is hot and cold with her when she first integrates into the ADA. Hovering around her one moment and then trying to ignore her the next. He isn’t sure how to interact with her since the last time he did, he was essentially a different person entirely. His growth may not be all that dire to him, but to others it could be like looking at night and day. Dazai doesn’t want to accidentally trigger anything that could make her dislike him, but he does want to stick close enough to her to keep her safe. Finding her half dead in an alley and then having her wake up with no memory of herself or him was a feeling he wasn’t prepared to rationalize or easily accept. 

When he finally gets over it- much to her interrogating him and backing him into a corner to admit everything about his behavior- his attitude is much more comfortable. Sticking close to her as much as he can without coming off as suffocating, he convinces himself it’s because he wants to figure out what happened those two blank years he was in hiding and nothing more than that.

Dazai is clearly affectionate towards Alice, but he would always make sure not to go over the top. Conflicted because does he love her or is it just the idea of someone loving him in a way he can digest by not trying to crawl under his skin that's appealing to him? Or was it just because he wanted to know what happened to her when he left?

Why did he want to know in the first place?

It confuses him and sends him into conflicted spirals if he dwells on it too long. Dazai often only tries to go down roads of "self-discovery" while looking down into a half empty glass of whiskey.