Demonic Qi!
The moment the black light rose, Ye Fan confirmed, this was the purest demonic qi.
Demon does not mean truly evil; pure demonic qi is also a type of power in this world, just oftentimes not accepted by the world.
The thoughts of good and evil lie within one's heart; a heart inclined to good is good, and a heart inclined to evil is evil. Cultivators of orthodox Cultivation Techniques are not necessarily good, and those practicing Demon Techniques are not necessarily bad.
It's just that Demon Techniques are not tolerated by the world, considering those who practice them to be thoroughly evil and treacherous characters.
However, Demon Techniques in most cases will corrode a person's Divine Soul and mind, ultimately turning them into a mere killing machine.
