Reiryoku

Reiryoku, otherwise known as Spiritual Power, is a power that all humans and spiritual beings have that is aligned with the person's spiritual sensitivity and willpower. Every human and spiritual being has a certain amount of this spiritual power with which they can power various superhuman abilities if their amount of Reiryoku is higher than normal.
Amongst living humans, above-average levels of Reiryoku are extremely rare and those humans that have a higher level of Reiryoku gain the basic ability to see ghosts, including Plus Souls, Shinigami, and Hollows. Shinigami and Hollows are souls that have extreme levels of Reiryoku through which they can use varying powers.

Spiritual Power Levels

Depending on a soul's spiritual power level, a variety of abilities can be used. The higher the level of Reiryoku, the stronger and more powerful abilities these souls can create and use.

Power Level	Description
Basic Reiryoku	Those with basic reiryoku possess a level of spiritual power that is very minimal. A common level of power for a regular human, this level of power is very common among those that may or may not be somewhat spiritually aware, but have no real spiritual power. (Below Average-class)
Average Reiryoku	Those with average reiryoku possess an average level of spiritual power. A common level of power for low-ranking seated and non-seated members of the Gotei 13 or lesser power individuals, this level of power is very common among those that have significant spiritual awareness and may possess powers of their own. These power levels can differ greatly among individuals. (Average-class)
High Reiryoku	Those with high reiryoku possess an above-average amount of spiritual power. This power is finely controlled, often common among those of an average Lieutenant rank and high-ranked seated officers. (Lieutenant-class)
Great Reiryoku	Those with great reiryoku possess a large amount of spiritual power. This power is finely controlled, often common among those of an average Captain rank. (Captain-class)
Immense Reiryoku	Those with immense reiryoku possess an enormous amount of spiritual power. This power is finely controlled and is reflected by its ability to enhance its user during combat and its ability to affect the environment around the user on a controlled level, allowing the user to utilize the power in combat to startling degrees. (Advanced Captain-class)

Sensing Reiryoku

Those with higher-than-average levels of Reiryoku have abilities far beyond just the ability to see ghosts, as they also have the ability to sense other spiritual beings without relying on the use of their five basic senses. Every spiritual being emits a portion of their Reiryoku in the form of Reiatsu which can be sensed by others. This ability tends to require some skill but can be achieved and heightened with training.
All spiritual beings have a unique pattern to their emitted Reiryoku. After some time, one can recognize the pattern of their friends and acquaintances with the ability to sense their presence and physical and mental states from large distances. Changes in these emitted patterns of Reiryoku can mean that the person in question is under great stress such as during combat or has suffered a grave wound.
The patterns of Reiryoku vary greatly between different types of spiritual beings. For example, the emitted pattern of Reiryoku for Hollows is easily distinguished from the patterns of Plus Souls or Shinigami.
The presence of Reiryoku can be blocked in a few different ways. The usage of Sekkiseki, a special stone that blocks the presence of Reiryoku from either side of the material, is common, as can be seen in the walls of the Seireitei. This material can block even the strongest of Reiryoku, inhibiting the sensing of Reiryoku patterns.
Any spiritual beings with extremely high Reiryoku cannot have their Reiryoku sensed at all by less powerful beings. Those with high spiritual power do not need to conceal their Reiryoku for less powerful beings to not sense it.

Kanji

霊力

English

Spiritual Power

Type

Metaphysical, Arcane

Controlling Reiryoku

The emission of Reiryoku is a natural phenomenon, but a spiritual being can control the level of this emission through the use of skill and training. By blocking the emission of their Reiryoku, a spiritual being can completely hide their presence from others. Amplifying one's emission of Reiryoku, known as Reiatsu, can be considered a show of force, a way to intimidate others, or even attack if needed. In some instances, this can paralyze opponents and cause damage to people and things within the surrounding area.
Other than controlling the amount of Reiryoku that one emits, spiritual beings can also use their spiritual power to help them perform supernatural feats. These feats often require some concentration and will tire a person out after long or successive uses. It is known that beings such as Shinigami need to eat to replenish their strength after excessive usage of their Reiryoku but beings such as the regular Souls that dwell in Soul Society do not.
High-level Shinigami, such as Captains and Lieutenants, have such high Reiryoku, that they can cause undesirable ripples in the World of the Living. Those of high spiritual power receive a seal upon them whenever they pass through the Senkaimon from Soul Society to the World of the Living. This seal limits their strength to about twenty percent of their maximum output. In critical situations, this seal is not used.

Other Uses of Reiryoku

Other than Reiatsu, Shinigami use Reiryoku to:

• Cast Kidō spells
• Increase their speed (Hohō)
• Use the abilities of their Zanpakutō
• Increase their physical strength and power

Other spiritual beings, such as Hollows and Arrancar condense their Reiryoku and use it for offensive purposes. They can also increase their speed and use special abilities through the use of their Reiryoku.
Quincy use their Reiryoku to increase their speed and form their weapons. Their use of Reiryoku is fundamentally different from other spiritual beings in that they gather Reishi from the environment and use it for various things.