Chapter 1

X: Immortals born under certain categories of the supernatural spectrum.
Mortals: Humans with no abnormal abilities

Subject X: Captured immortals to be tested on in order to find a cure so they would become mortals.

After the death of Lieutenant Kim Namjoon's family after they were exposed to being a family who are able to cast spells, Namjoon fed on this urge for revenge.
So what did he do?

Well he was going to rebel, but he's going to need more than just his hidden spells for that to happen, and who's better than the very first Subject X who were tested on?