dark knight is the knight of chaos/confusion.
dark knight are not dark.
The Dark Knight is the embodiment of human anger and sorrow, funneled into the form of a warrior of darkness.
Soul of Chaos: A skill that enables one to become a Dark Knight. A number of character stats will go through a significant boost, while the character will be temporarily equipped with Dark Knight Armors. If this skill is sustained for longer than the allotted time, the power of darkness will become unbearable and start applying negative pressure to the body. It's only available once a day in Erinn time.
Control of Darkness: Through the power of control that stems from the darkness from within, this skill allows one to control animals or Fomors in the vicinity as his/her own. The more powerful the opposition is, the more resistance it will have against this skill. Once the animal or Fomor is in control, however, the stronger the opposition is, the harder it is for the monster to escape the grip this skill has on it. This skill requires a special Fomor Scroll, and apparently, this scroll can easily be obtained through other humans.
Underlined to support my point.