I don't get it, can someone explain what happened in this arc?
Basically: the cult was built around a prophecy that most interpreted was about the founder, Sui's grandma, coming back as a god and using Sui as a vessel. Instead, turns out she had god-like potential all along, and her grandmother's spirit was the prophesized obstacle that would try to hinder her ascension.
The cult was also taken over by Seteth, who wanted to take advantage of it to build power. He had no clue there was actual supernatural forces at play. Hama's dad also joined for some reason, but has now left with Yume and Hama (who got teleported there somehow, either as part of the home delivery job teleporting her or maybe being dragged there by Sui).
I think there's absolutely more to this arc's story though that the arc itself hasn't addressed. Specifically, I don't think we ever got a proper (or even vague) explanation for why people's brains were being removed by the cult, and lots of the stories in this series seem to directly involve brains. Not to mention this arc confirmed Hama's mystery illness involves her brain scan showing a second brain overlapping it, and Sui had the same thing. Which turned out to be possession in Sui's case. And Yume's mom also possesses people.
So basically, I think there's some interconnecting thread/plot directly related to brains, probably tied to that Q organization.