As Kiriha held back the radical faction, she began using underground technology in an attempt to treat Sanae.
But as she continued her investigation, Kiriha ran into a big wall. And that wall was that the Sanae in the hospital was conscious.
If the ghost Sanae had just been a soul that had escaped its body, it would have been so simple. It would just be a simple matter of using the People of the Earth's spiritual energy technology to bind her soul to her body. There had been several examples of that happening in the past. However, the Sanae in the hospital could function as a normal person. And this considerably confused Kiriha.
But at the same time, Kiriha could understand a few things. The hunters had targeted Sanae because she was a forgotten, loose spirit. If her real body could move on its own, nobody would be troubled if they captured Sanae. To them, she was the perfect target, and they would have a clean conscience knowing that her parents wouldn't be hurt.
And as she continued her investigations, she learned that the ghost Sanae with Koutarou and the others was a piece of her spiritual energy that had separated from the main body and became a ghost.
A few years ago, spiritual energy began separating from Sanae's soul which caused her body to grow weaker. Eventually, her parents noticed how weak she had gotten and took her to their own parent's home. After that, the real Sanae had been admitted to the hospital, and Sanae's spiritual energy that had been left behind in room 106 began its activities as a ghost. After chasing out several tenants, Koutarou eventually moved in. This was the reason behind why Sanae had been in room 106.
Kiriha didn't know why the spiritual energy had separated from Sanae's soul. It might have been a condition she had been born with, or her soul might have received a huge shock in the past. Regardless of the reason, Sanae's current condition was troublesome.
With the majority of her spiritual energy being with her ghost half, the real Sanae grew ever weaker. And after these years, she was now in an incredibly dangerous condition. It was necessary to merge the ghost and the body as soon as possible.
But that was the problem. To return Sanae to her original state, they would have to return all of the spiritual energy that the ghost had. They need to reattach the parts that had separated back to her soul that had separated. But this kind of thing was a first even for the People of the Earth, and they didn't have any technology for it. Because of that, a large amount of time to develop it was needed. In order to keep Koutarou and the others from worrying during the long time it would take, Kiriha had continued her preparations without telling them.
However, Sanae was growing weak at a faster rate than the progress on the technology was being made. And tonight, she had weakened to the point where it got difficult to maintain her life. Since the real Sanae had started to die because of a severe lack of spiritual energy, the ghost Sanae was about to disappear as well.