|Yin Yang Master|
|Yin Yang Arts|
|Yin Yang Ways|
The Yin Yang Ways (陰陽道) is JAPAN's counterpart to magic, developed by Geppei (月餅, "Mooncake") around the early NC0700's. Much of its focus has to do with the sealing of Hell Holes and the suppression of Ogres. About a hundred years after the invention of the Yin Yang Ways, the study, research, and practice of Yin Yang became structuralized, developing into the Yin Yang Arts (陰陽術).
Unlike common magic, the Ying Yang Arts are all performed though paper mediums known as "rei". There are generally two types of rei: shiki rei and summoning rei. Rei are created by writing special characters/glyphs onto paper. Higher level reis typically have more characters of greater complexity. People with ugly calligraphy or a clouded mind tend to fail in making reis. A rei can only be used by the person who created (wrote) it.
Those who uses rei to perform Yin Yang are known as Yin Yang Masters (陰陽師; "Diviners" in the Yandere translation of Sengoku Rance).
The Houjou House has been the major center for the Yin Yang Arts for at least 500 years.
Shikifuda / Shikigami
A shikifuda, when used, turns into a shikigami to do the Yin Yang Master's bidding. Low level shikigamis usually look like origami (folded paper), although high level shikigamis may have a variety of appearances.
Many types of shikigami exist. Some are capable of attacking, while some are used as barriers to block attacks. Some are used to rely information across great distances, and some can be used for spying.
Depending on the strength of the Yin Yang Master, the number of shikigami they can command at once, as well as the abilities of the shikigami, can vary greatly.
Because shikigami are made out of paper (shikifuda), they are extremely weak against water and fire.
With the Summoning Rei, a Yin Yang Master may temporarily summon something from somewhere else to do the summoner's bidding. What gets summoned typically correlates to the Yin Yang Master's abilities, with an Ogre being the typical result of most summons. However, sometimes monsters and even other humans may get summoned. After the time limit of the summoning rei has passed, the summoned being will be returned to their original location, without much of the memory of what has happened.
When a creature/thing gets summoned, it'll usually be forced to obey the summoner's commands. However, on rare occasions where an Yin Yang Master manages to summon something much more powerful than what their abilities are supposed to be able to manage, the summoned being might not listen to the summoner and may in fact attack the summoner.
While usually the summoning Yin Yang Master doesn't have much active control over what gets summoned (there's a semi-random factor), advanced Yin Yang Masters may be able to "tame" a particular creature they have randomly summoned. Once "tamed", the Yin Yang Master may be able to freely summon the same creature in the future.
Yin Yang Rank Levels
- Yin Yang Level 1 -- Able to make normal shikifuda and summoning rei. Only able to summon low level Ogres.
- Yin Yang Level 2 -- Fully mastered the arts of Yin Yang. Has the ability to "tame", and thus to summon specific beings. Example include the Houjou Souun during early LP era.
- Yin Yang Level 3 -- Legendary. Capable of taming beings of great strength and summon them at will as servants. The only currently known example is Houjou Souun the First.