Oh no! That's not good. Okay, let me see if I have this right, since it's been a while...
So, our "Dara-san" can feel a malevolent spirit sleeping inside of her, which she's constantly fighting to keep sealed. We are led to believe that this is the soul of Aragami, the evil serpent spirit, since that's naturally what the younger sister priestess had merged with, in the past. However, that snake spirit has already escaped, attached itself to someone else, and has turned into a funny mascot friend who is evil but mostly harmless. Despite this, Dara-san still feels as if she's playing a tug-of-war with her "other half", but it hasn't been clear if that's still a real threat, or if Dara-san has simply not noticed the serpent's absence.
Separately from that, we have this ongoing story in the past, where Jurota is working to set up the spiritualist faith in the Yamagami, and there's this odd quirk of the younger sister priestess' name constantly being kept hidden. In terms of story structure, the biggest mystery is why we're even seeing these events at all; at first, we were just getting the origin story of Dara-san, but we've long since passed that point now, and it's mostly seemed like inconsequential housekeeping that could've easily been sunmarised by simply saying "Jurota helped set up these traditions in reverence for the younger sister priestess", and left it at that. Moreover, what possible significance could her old name hold, after all this time? Why even hide it? It seemed like a strange choice.
This chapter is finally giving us the answer to all of these questions. The malevolent "other half" that Dara-san had been fighting against wasn't the serpent god, but her own older sister; she had sealed her own name away, because it was spelled the same as her older sister's name, and recalling her own name of "Koharu" would risk recalling the name of "Tsubaki" and empowering the older sister to awaken; and we're still following the story of Jurota in the past, because the preparations he made to establish Koharu as the dominant personality is presumably going to be vital in allowing her to reclaim her body from her older sister, and maybe even help to seal her away for good.
If I've gotten off-track anywhere, I would appreciate the correction, but this seems absolutely phenomenal. I can't believe how good this story is at handling its folk horror elements and tragic romance when it's like 50% composed of crossdressing children getting weirdly horny about monster milfs. Just crazy.
