It is just my guess, but he must have drunk something which resulted in his magic power going out of control... moreover, because he can't release it outside, his magic power was pressuring from inside his body and his body couldn't endure it... if this keeps up, his internal organs and blood vessels will explode. It is also possible that he will be weakened to death due to a large amount of hemorrhaging... I am requesting a blessing unto this location, "Ten Thousand Heavens."
Concluding so, Kaori chanted her healing magic. "Ten Thousand Heavens" was what she activated. It was onne of the middle-ranked healing magics with the effect of curing abnormal conditions. It was the magic used to undo Suzu's petrification.
However...
"...There's almost no change... why? For it to be incapable of curing it... does it means too much time has passed?"
Apparently, "Ten Thousand Heavens" could not cure the man, it could only delay the progression. Next, maybe because of the pressure from inside his body, the young man groaned in pain. His bleeding didn't stop. At the moment, because she didn't have any clear treatment method, Kaori ground her teeth and decided to use her emergency measure.
"Here I declared the light of grace, here is my realm, my sanctuary, which crushes all evils just as I intended to, "Holy Ground.""
High-ranked light attributed healing magic, "Holy Ground." It was a magic that transfers peoples' magic power to the others within the area. Basically, by transferring one's magic power to one's companion, that person would temporarily escaped from magic power exhaustion. It was a magic that aimed to supplement another if s/he didn't have a sufficient amount of magic power to shoot a strong magic.
Moreover, it wasn't limited to the user's magic power, so it could forcefully transfer someone else's magic power to another within the area. It held the same principle as magic drain. However, it needed a lot more time to extract the magic power from another person and it was impossible to extract a lot of it at once. This was the reason it is only a "High-ranked magic."
To begin with, it only became practical because Kaori was capable of activating magic which originally needed ten notes with only three notes of chanting. It showed how capable Kaori was.
The reason she used this magic on the suffering young man was of course to release the rampaging magic power that was building pressure inside his body towards the outside. It was displayed on the status plate that the young man was in state where he "cannot release magic power to outside of the body," so she decided to try "if" it could be solved by forcefully draining it using high-ranked magic.
The pure-white light expanded from the center of the young man's body, and firefly-like, fleeting lights sprang about. It was a mysterious sight. With her eyes shut, the appearance of Kaori, who placed her hand on the young man's chest as she concentrated and was wrapped by the fleeting light, was divine.
Kaori, who easily activated high-ranked magic, made the ones well versed in magic, Yue and Tio, inadvertently leak "Hou...," voices of admiration. While being held by Shia, Myuu watched Kaori in an entranced expression and muttered, "Beautiful...