If "elements" are an integral part of the story … who's who?

1. Water = Jang Uk & Nak Su = only ones who mastered Tansu
2. Fire = ???
3. Wind = ???
4. Earth = ???

The question is, are they following æther (Western/Japanese) or metal (Chinese/Korean) elements?

• Æther (Western and Japanese fifth element) = Bu Yeon = energy
• Metal (Chinese, Korean fifth element) = ???

All five elements together = Light = pure energy = power from the heavens = Ice Stone.

The anti-thesis of Light is Shadow, thus the anti-thesis of all 5 elements:

• Shadow = Jin Moo (shadow = copycat; fake; sinister; evil; selfish)