Deadfish? Really, Bill? Not that I care, taking everything from bots, but that's just sad.

Hoshijiro had a dead flag hanging over her from the beginning. I assume Izana is the real deal, and Hoshijiro was merely a device to develop both Tanikaze and Izana. Obviously Izana has liked Tanikaze for a long while now, but perhaps now enough to go for the female gender in order to be with Tanikaze as a girl. I guess that third gender needs to decide sooner or later which one to become. It was a bit cruel Hoshijiro got such nice development despite being doomed to die, but of course it wouldn't otherwise have had much believability.

I feel like this was quite annoying dramaturgic play, though, to skip the fight and only show the end result. Naturally it was effective in the sense that Tanikaze's amnesia was this way shared with the audience, but I can't help but think we missed a badass fight where Hoshijiro heroically sacrificed herself to save Tanikaze.

Kunato being the real reason behind this sounds quite plausible. That man is a real snake.