It seems to me the easiest explanation here would be that Iorogi was forced to accept a deal of coaching Kobato through the bottle filling affair in order to teach him a lesson. From Ginsei and Kuma's speeches you get the impression Iorogi used to be quite a ruthless and single-minded character before.

Now it would be nice to actually learn more about Kobato herself. What is she, even? A celestial, obviously, but quite a miserable case of strange circumstances. Those circumstances would be the big question mark.