I love how Kaisei has always been here since the first color page, we only see his back opposed to Akane and closer to Issho, but cuz the composition is in 3 different areas (? He's in the panels with shinta, masaki & little akane, which means he's important to the plot. He's one of Akane's cores.
But even in the volume extra pages, there was only the back of his head, because Akane were chasing him. Kaisei is his rival, and his goal. Like she wants to kick Issho, but she also needs to kick Kaisei. And they very cleverly made this point since the first color page.
And then, we keep doubling down on this because we also have this interactions
And
And my absolute goat









