So I've always been fascinated by the implications of this back and forth from chapter 63, Chains. This happens before the 104th along with Hange reach the chapel where Eren and Historia are held and Levi debriefs them all on Kenny and what kind of opponent he is, an opponent that scares even him, if we are being very honest. But Hange says something interesting and different from the others about Kenny as they ask Levi: "How is it you don't know more about Kenny the Ripper? Didn't you live with him?"
And that dialogue coming from Hange is interesting because it implies two different interpretations of the events unfolding: 1) Hange knows that Levi used to live with Kenny because he told everyone present in that carriage beforehand while he was explaining Kenny’s skills or 2) Hange knows about this detail because Levi already told them about his past in another conversation they both had prior to this scene. Hange couldn't have known from the conversation Levi had with Nifa when he told her out of nowhere he used to live with Kenny before her death since Hange was not present with them at that time. So then that would mean Levi could have told Hange at another time offscreen from the manga.
The second reasoning then implies that Levi trusted Hange enough to open up about his past to them. And I think the second reasoning is more plausible than the first since it’s only Hange who asks him a question linked to his past, unlike the others who only muse about Kenny and how hard it will be to beat him as seen in the panels below mostly coming from Connie, Sasha, Armin and even Hange. But that specific line is very different from the bit of dialogue where Hange reflects on who Kenny is as a fighter. The way Hange asks their question about Kenny's place in Levi's life doesn’t feel as if Levi already told the group about him and Kenny living together in the past, meaning that it could be a piece of information only Hange knew about him.
And if we go with the second reasoning (but both interpretations are valid), then it solidifies the trust Levi has for Hange and vice-versa, going so far as to open up about his past to them, which is an interesting touch and maybe another mystery we will never be able to solve in Levi and Hange’s relationship. But the traces of Hange knowing bits of Levi’s past (and especially the past surrounding Kenny) are definitely there.
