I think this chapter really signals for me that the end is near for arc 1. I can't really imagine Sera and Nat's relationship being mended until the big climax, but I also can't imagine their relationship staying like this for more than another volume and a half or so.
I really wonder what's going to happen to all these characters original to the serialized version when Ventfluer is destroyed. I can't really imagine any of them journeying with Sera and Nat, that would seem to go pretty fundamentally against the premise of arc 2, but I'd be pretty sad to see them go. If Ena and Leah really are to exit the story, maybe the ship teasing this chapter could be leading to a conclusion for their characters? I feel like they could have a lot to learn from eachother, and having someone they care about would do a lot to temper both of their flaws. I'm just writing fan-fic at this point, though.
Also, did you know that since the physical volumes 4-5 are amazon self-published, you don't actually need to pay for shipping from Japan? I just got mine a few days ago and the print quality is much better than I expected, although unfortunately the spines don't actually match up with the older volumes.
As always, thank you for the TL!