Ashin

Ashin (亜神, "Demigod") are a unique type of transcendent s who boast enormous power.

Overview
Technically, Ashin are not a separate "race" of Souls but rather a kind of classification for certain exceptional spiritual beings. A few "genuine" Ashin might exist to assisst a full-fledged deity in the profound task of maintaining a universe in functioning condition. Be that as it may, for all their scarcity their numbers are not limited to those few veritable entities. In fact, there are some ways to become an Ashin. The offspring of a transcendent being like the Soul King and an ordinary Soul will be born an Ashin by default. However, it is possible for normal spiritual entities to transcend the fundamental limitations imposed upon them and obtain divine qualities through a protracted and arduous process of comprehensive development.

Appearance
Whilst the physical appearance of Ashin varies greatly there are some common features. For instance, genuine Ashin tend to assume highly unusual forms unlike that of any regular spiritual beings. Conversely, those who have attained the status of an Ashin or were born a hybrid usually retain the innate traits of their mortal ancestors yet at the same time display certain otherworldly qualities that most would consider "grandiose".

Attributes
The Ashin share a number of supernatural traits:
 *  (永生, "Eternal Life"): Ashin do not age and they are not subject to death of natural causes - both time and diseases have no bearing on them. For all intents and purposes they are nearly as timeless as true deities. A side effect of their nigh-perfect physique is that they recover from grievous injuries and severe mental trauma at significantly increased rates. Regardless, whilst they are perdurable by definition, it is, in fact, possible to destroy them with appropriate force.
 * Chōetsu (超越, "Transcendence"): Whether a genuine or artificial semi-deity, every Ashin is characterised by a distinct concept-type special ability. In the case of those who have ascended to this status, this power often expands upon their natural abilities from before the transformation to an appropriate level. Nevertheless, those signature powers exist beyond the limits of normalcy. Their magnitude is impressive and their scope broad. Moreover, Chōetsu is by definition highly complex in nature and as such might be difficult to comprehend by ordinary spiritual beings.
 * : All Ashin have a colossal amount of spiritual energy at their disposal. Whilst gifted spiritual beings might boast enough energy to exert their influence on the surroundings in a very palpable manner, Ashin exist in a league of their own. Their ability to affect the environment may reach as far as to a regional level so that an entire area might crumble at their sheer approach. Their reservoir of energy is sufficient to continuously cast what ordinary entities would consider high-level techniques with little to no signs of fatigue. Furthermore, the potency of their is so overwhelming that they are capable of ruining settlements and suppressing armies with their willpower alone. Even the power of a Captain-class barely registers next to the divine might of an Ashin.

Ascension
The nebulous process to become an Ashin is protracted and demanding. Whilst gifted spiritual entities might fulfil some of the criteria during their natural progression certain other requirements pose almost insurmountable difficulties. Due to the process's intrinsic complexity an extended period of time and arduous efforts are essential. Moreover, the vast majority of spiritual entities are not only ignorant of the most abstract criteria but even of the sheer existence of the transcended state in the first place. Effectively, this means that very few beings might attain the status throughout the entire history of the Spiritual Realms. Some of the known criteria include:
 * s, and by extension, s and the, cannot become Ashin as long as they maintain their physical bodies.
 * Togabito are incapable of achieving transcendence when bound to Hell.
 * Peak Condition: The physical aspect of a being is vital. Frail body will not be able to withstand the unimaginable stress of enormous power that comes with transcendence.
 * High Intellect: Simple-minded being cannot achieve the state due to the fact that considerable mental faculties are required to methodically and successfully pursue the extended process of development that may lead to ascension. The individual must be ingenious and astute to not only easily learn new skills but also come up with one's own ways of improvement. The ability to comprehend intricate concepts and solve complex issues is essential.
 * : Each sentient being possesses an amount of spiritual power at one's disposal. Most of the time every entity boasts a fairly specific level of potential. Of course, it is entirely possible to increase spiritual power through extended training, assimilation and/or certain artificial means. Nevertheless, relatively few beings reach the degree of might that renders them eligible for ascension because even an average Captain-class entity is too weak. However, once that treshold is surpassed by a wide margin the amount of Reiryoku may eventually become sufficient to power the potential process of transcendence.
 * Tenkei (天啓, "Revelation"): Honing one's combat skills is a viable means of achieving the divine state. Regardless, even the most proficient of Advanced Masters are far from the transformation. The achievement of the absolute limit is inevitable and at some point it becomes virtually impossible to progress any further through conventional means, no matter how strenuous or creative. Still, that process is crucial to prepare the individual for the occurrence of Tenkei. Select few beings who have reached the pinnacle of achievement may eventually experience a unique esoteric revelation that allows them to ultimately transcend the boundaries that contain the vast majority of Souls within the confines of normality. The so-called Grandmasters are in a league of their own when compared to any ordinary spiritual entities. However, this event is not enough to become an Ashin on its own.
 * Nijū de Tōitsu (二重で統一, "Unity in Duality"): Arguably, the most restrictive criterion. There exist many races of distinct spiritual beings who each boast different qualities. In the end, no pure spiritual entity might achieve elevation due to their inherent, if somewhat paradoxical, incompleteness. Obviously, natural hybrids are exempt from this. Conversely, those of pure heritage who wish to ascend have to acquire the traits of another race through artificial means, such as the . Such a dual entity must then seek genuine unity in this new state to become eligible for transcendence. With the attainment of such unusual totality one finally becomes ready for ascension.

Shōten (昇天, "Ascension"): Currently, next to nothing is known about the occurrence of Ascension. What little is known is that fulfilling the above criteria is not enough to transcend outright. Rather, the spiritual entity in question must seek to uplift oneself with the use of unique powers obtained throughout the development. However, how to achieve that or even whether this is all there is to the event is, for the time being, unknown.

Trivia

 * The concept of Ashin was partially inspired by 's -powered attempt to become a transcendent being that surpasses both Shinigami and Hollows. Aizen had managed to fulfil most of the criteria to obtain godlike status but ended up one step short of genuine ascension. In the eyes of the concept's creator, Aizen failed because he was simply too young; in spite of his exceptional prowess he had yet to experience Tenkei.