Why do people think ogata suddenly cares about asirpa at all? Because he said hinna hinna a couple of times? He killed his own brother and father in cold blood. I literally have no idea what he wants.
The relationships in this manga go from being really skeevy (like ch.23) to super wholesome. Also, a 13-15 year old girl can't "have an affair" with a married middle-aged man, that's grooming and rape.
The bone divination probably foretold the death of one of the other characters in Asirpa's group, I think it will either be Ogata or Sofia, maybe both. It only happened once Shiraishi decided to join them because now he is probably going to be the deciding factor in assuring Sugimoto's group...
Not too sure why the author decided it was a good idea to straight up tell us that Gin's friend has feelings for him rather than showing it through actual character interaction and plot progression?