Heki

Heki ( 劈, lit. Burst ) is the spiritual essence of an individual in Regalia that can be harnessed into a physical, corporeal, form through training or extreme emotion. Most characters within the Regalia universe can manipulate Heki to some degree, with the most powerful users sitting comfortably at the top of the |Yakuza Yakuza underworld. Though Heki is most often used by members of the Yakuza, recent events have shown that the Shinsengumi are also capable of this feat.

About
Heki is to Regalia what Reiatsu is to Bleach, or Reiki was to Yuu Yuu Hakusho. As stated above, most characters within the Regalia universe possesses the ability or potential to harness their dormant Heki into a physical form, from there it's use can be applied to various things — but it's generally received as most useful on the battle field. It's very rare to find two identical forms of Heki as it differs depending on the individual.

Aged scrolls examined by scholars find that Heki was first introduced to the world through the Yakuza, and many believe the myth that Susano-o himself taught three individuals the art. It's said that after their training was completed, Susano-o presented them each with one of three Regalia and charged them with their safety. While this theory does have it's nay sayers, with the reality of three sacred Regalia treasures being heirlooms of three Yakuza families, how could you deny this claim?

While there are no set appearances of Heki, they are distinguished by three basic types:

Godai
Godai ( 五大, lit. Elemental ) is the most common form of Heki with it's appearances generally mimicking one of several earthly  elements. Godai-type Heki, although mimicking elements, will come in any sort of color even if perceived as odd — i.e. red water, pink wind. It's also found that severe reactions to certain situations or objects can cause a color alteration  of&#160;the individual's&#160;Heki.

Shimoni
Shimoni ( シモニ, lit. Consumable ) is unique in itself. Unlike Godai-type Heki or Saibou-type Heki, a person who possesses Shimoni-type Heki gains strength by consuming a certain object — whether it's liquor, meat,  or even fabric. Typically, a Shimoni-type Heki user is deemed as valuable as the source material he/she carries.

Saibou
Saibou ( さいぼう, lit. Biological ) is the rarest type of Heki. These lucky few gain the ability to increase one, or all, of their five senses through an enlightened understanding of their bodies biological make up. The dominant Saibou-type Heki users in Regalia are most often from the Souma family — which is understandable given their immense wisdom in all things.

Psychological
Sometimes individuals who possess rather intense Heki can use it in such a way to instill fear into opponents, sort of like a killing aura. A prime example of such use is when Kasui Hideta unintentionally sent out such a violent killing aura that several lively birds within his vicinity suddenly, and literally, dropped dead. There is also another way to use this form of Heki rather then scaring opponents, and Adachi Sayaka is the only person who has displayed such so far with her danger sense.

Offensive
Heki is most commonly used in this method and is often thought of — whether it's Godai, Shimoni, or Saibou — that there is no other greater use for it then on the battle field. However, being proficient in manipulating your Heki for offensive purposes will mean nothing without proper combat training. A perfect example of a great combination of Heki-manipulating techniques and extensive combat training can be found in the Bloody Palace Arc where a quite interesting battle took place. Outmatched by Kasui Hideta and Ishida Yamato, the confronted Eclipto utilized his form of Saibou-type Heki to divide his form into two copies, then proceeded to battle his adversaries to fairly successful results.

Defensive
A Saibou-type user, with the knowledge, could effectively use their Heki to dramatically increase their defense to the point where even extremely sharp objects couldn't pierce them. Though, defensive use isn't exclusive to Saibou, as it can be used by the other two types if the circumstances are correct — i.e. a Godai-type user with the affinity for the wind element could create a stationary whirlwind that would redirect lethal objects away. Or, a Shimoni-type user could devour fabric and spew out a wall of protective thread that mimics a spider web.