Hollow/Arrancar

Hollow (虚 (ホロウ), horō) are a race of creatures which are born from Human souls who, for various reasons, do not cross over to Soul Society after their death and stay in the Human World for too long. They are corrupt spirits with supernatural powers which devour the souls of both living and deceased Humans. Hollows settle in Hueco Mundo, but can cross over to the Human World and Soul Society. Hollows are the opposite of Humans.

Hollow are former Pluses (deceased Human souls) who lose their hearts to despair or regret, or they remain in the Human World for too long. Any spirit who is not guided to Soul Society by a Shinigami via Konsō may eventually turn into a Hollow.

Transformation Process

The majority of ghosts peacefully move on to the Soul Society after their deaths. However, some stay in the living world to fulfill certain goals, such as looking after a loved one, protecting a particular location, or pursuing a grudge from beyond the grave. However, with only limited abilities to interact with the living, and by definition tied to their goals, many ghosts find they are unable to cope when their loved ones move on or old enemies forget them. At this point, some will become dangerously obsessed with fulfilling those goals, even if the means to fulfill them renders the soul empty: for example, killing anyone who comes near a loved one in order to keep them from hurting that person. In doing so, the ghost warps into a Hollow and, ironically, often makes the focus of their obsession into their first victim. This can be prevented if a Shinigami gives the soul a Soul Burial before it turns into a Hollow. The process by which a soul becomes a Hollow usually takes months to years to complete, reflected by the length of the soul's Chain of Fate, which usually resides in the center of their chest, and connects to their bodies, if present. The Chain of Fate slowly corrodes over time, coinciding with the degradation of the soul's ties to the living world. The process can be accelerated under certain conditions, such as being attacked by a Hollow, giving into extreme despair, or using certain spiritual powers. When the chain completely decays, they become a Hollow when a hole opens up on their chest where the chain was attached, signifying they have lost their heart.

Tendencies

Once a soul becomes a Hollow, it is driven by an eternal and insatiable hunger to devour other souls, living or dead, to fill the void caused by its descent. While their former obsession often becomes their first target, most Hollows will eventually become mindless creatures concerned only with finding the most potent souls to devour. Stronger and more evil Hollows are often able to retain some of their intelligence in Hollow form, making them more dangerous than the average Hollow. While most Hollows are evil, or at the very least mindless, at least a few are not, and hey are at least partly capable of camaraderie and loyalty,.

Appearance

All Hollows wear masks, which are formed from the hearts they had lost as Humans. This mask protects the naked instinct which is left in a being after the loss of its heart, and obscures the original identity of the Hollow. The masks of different Hollows can differ greatly in shape and form, but are always white and skull-like. The mask can be shattered, temporarily allowing the Hollow to regain its original identity, but it will regenerate after a short period once the Hollow takes over again. Hollows have widely varying physical characteristics, rarely appearing the same. In terms of appearance, Hollows can range in appearance from furry (like mammals) to lizard-like to outright demonic. Hollows vary in size, though it tends to be fairly consistent among the various classifications of Menos. In Hueco Mundo, some Hollows are no larger than common pets. Most common Hollows are about twice the size of an adult Human, though it can vary to a degree. It is revealed by Kūgo Ginjō how Hollows gain their unique appearance and individual powers. When a Hollow's heart is carved out by the hole in their chests, the lost heart becomes its mask and changes its outward appearance to what it looks like as a Hollow. The powers a Hollow wields are manifestations of its heart.

Destruction

Hollows are usually killed by splitting their mask and head in two, but most wounds which would be fatal for a Human will effectively dispatch them. When this is done by a Shinigami's Zanpakutō, the Hollow is not truly killed; its spirit is purified of the sins it committed as a Hollow. This allows the spirit within to enter the Soul Society as a Plus. In cases where a Hollow committed great sins as a mortal, its purification will summon the gates of Hell, through which the soul is dragged to its punishment. When a Hollow is killed by a Quincy, it is destroyed, soul and all, which has potentially disastrous effects on the spiritual balance of the worlds. A Hollow's spiritual power is essentially poison to Quincy, and would destroy their souls completely should it enter their bodies, with no chance of even Hollowfication to occur. It is for this reason that the Quincy sought to destroy Hollows completely, as a philosophy of preserving their own existence.

Demi-Hollow

A Demi-Hollow (半虚 (デミ・ホロウ), demi-horō; lit. "Half-Hollow") is a Jibakurei, an earthbound spirit who is evolving into a Hollow. It usually takes a while for the earthbound spirit to fully transform into a Hollow, but this process can be sped up by forcing the hole in their chest to open. The Demi-Hollows are held down by chains, usually to a place they consider to be their territory. They are usually only seen when a Human steps on their territory and cannot be easily sensed by Shinigami.

Menos Classifications

Though most Hollows are simply transformed Human souls, a sub-group of Hollows known as Menos (メノス,menosu; Spanish for "Minus" or "Less"), exist. Menos are conglomerations of hundreds of normal Hollows, resulting in a single composite entity of far greater strength than any normal Hollow. Menos are created when the void within an ordinary Hollow's heart becomes so substantial Human souls are incapable of sustaining it, at which point it begins devouring fellow Hollows. These cannibal Hollows are attracted to one another, and a mass inter-devouring follows, resulting in a Gillian. Following this transformation, the Gillian can evolve twice more, first into an Adjuchas and finally into a Vasto Lorde, provided certain conditions are met. Menos evolution is not only contingent upon the Menos eating other Hollows, but also upon the Menos' ability to avoid being eaten. If another Hollow succeeds in devouring even a part of their body, evolution becomes impossible for the one who was wounded this way. Menos-class Hollows are considered so dangerous Soul Society sends only highly trained Shinigami teams to handle them. These incursions seem to be rare, however, as Menos rarely leave Hueco Mundo unless attracted by large sources of spiritual power or encouraged to by other forces. There are three categories of Menos: Gillian, Adjuchas, and Vasto Lorde.

Gillian (最下大虚 (ギリアン), girian; Japanese for "Lowest Great Hollow"), also called Menos Grande (大虚 (メノスグランデ), menosu gurande; Spanish for "Less Big" or "Big Minus", Japanese for "Great Hollow") are the first and weakest of all Menos. In Human terms, they would be considered foot soldiers. There are many of them, and they all look alike. In Soul Society, they are the "Menos" who are generally referred to in textbooks. Gillians are huge, but they are slow and have beast-like intellect. Any captain-level Shinigami can destroy them with ease. Up to the point when Rukia Kuchiki meets Ichigo Kurosaki, she had only seen them in such textbooks, despite having been a Shinigami for many years. Gillians commonly attack in a group, and one is powerful enough to be a challenge for a Lieutenant of the Gotei 13. Gillians typically arrive in the Human World through the use of spatial distortions called Kūmon (空門, lit. "Air Gate").

Appearance: Gillians are huge monster Hollows at least 2-6 stories tall, easily dwarfing even the largest standard Hollow. They all have a white mask with an elongated nose. Their bodies are covered from their head to their feet with a black covering reminiscent of a cloak. Around their neck is a row of thin white spikes. They have large, pointed feet wrapped in white bandages. They have large white hands with long, sharp, white nails, but they are commonly hidden within their cloak, rarely revealed even in combat. They have long tongues capable of breaking a fellow Hollow's mask.

Signature Skills: Cero, Kūmon, Negación.

Evolution: Though Gillians usually have no personality to speak of, which makes them dangerous since they have
no mind of their own, one of the many Hollows which comprise it might gain control over the newly formed entity, reflected in the unique mask it wears in comparison to a normal Gillian. Only these Gillian variants have the potential to evolve into Adjuchas-class Menos. The evolution is facilitated by the continued cannibalization of fellow Hollows, even other Gillians.

Adjuchas

Adjuchas (中級大虚 (アジューカス), ajūkasu; Japanese for "Intermediate Great Hollow") are the second classification of Menos. They are smaller than Gillians and far fewer in number. They are much smarter and stronger than Gillians, and are often the ones who lead Gillians into battle. Adjuchas are commonly solitary creatures, rarely joining into groups. They are powerful enough to challenge a captain of the Gotei 13.

Appearance: Adjuchas can vary radically in appearance, anywhere from bulky humanoids to the jaguar-like form of pre-Arrancar Grimmjow Jaegerjaquez.

Signature Skills: Cero, Garganta, Unique Individual Powers & Abilities.

Evolution: Adjuchas-class Menos are much smaller in population compared to the Gillian class, due to the rarity of any one Hollow being capable of overwhelming the many other Hollows which comprise the body of a Gillian. Furthermore, the Adjuchas must continue to devour Hollows, or its mind will be absorbed by the other Hollows comprising its form, and it will revert into a Gillian. The subsequent lack of an individual will prevent the reverted Gillian from becoming an Adjuchas again. If any part of an Adjuchas is devoured, they permanently cease evolving and possibly stop regressing into a Gillian, as the Adjuchas in Grimmjow's group asked him to eat them so they would not regress.


Vasto Lorde

Vasto Lorde (最上大虚 (ヴァストローデ), vasuto rōde; Japanese for "Highest Great Hollow") are the third classification of Menos and the highest level of evolution. They are extremely small Hollows, roughly the same size as humans, and are extremely rare in number. It is said that their entire number within Hueco Mundo can be counted with the fingers on one's hands. The combat capabilities of a Vasto Lorde are above those of the captains of the Gotei 13.

Appearance: Unknown.

Signature Skills: Unknown.

An Arrancar (破面 (アランカル), arankaru; Spanish for "To Tear Off", Japanese for "Ripped Mask") is aHollow that has removed its mask and has gained Shinigami-like powers. Arrancar are a group of Hollows that gained similar powers to that of a Shinigami by removing their masks. The individuals that Aizen turned into Arrancar using the Hōgyoku possess powers far beyond those of previous Arrancar. Arrancar are the result of Hollows removing their masks. However, an average Hollow removing their mask would not be a problem for the Gotei 13: to hold their own against the Gotei 13, the ones removing their masks would need to be Gillian or stronger. An Arrancar that was previously a normal Hollow, rather than a Menos-class, has been shown to be more powerful than some Vasto Lorde.

Arrancar and ordinary Hollows differ in several ways:.

Humanoid Form: A Menos usually takes on a Human shape when it becomes an Arrancar. The only ones that will definitely get a 100% Humanoid form are Vasto Lorde-class Menos. For the remaining two levels, there are many who don't get a completely Humanoid form, despite becoming Arrancar. Therefore, the closer one looks to a Hollow, the lower its power of reasoning. All Arrancar retain a hole in them somewhere, as well as fragments of their Hollow form (in the shape of protrusions and partial masks). Some Arrancar have claimed that they gave up their Human forms in order to obtain enormous power. While some Arrancar prefer to conceal the remnants of their past, others choose to hide their faces completely to escape unwanted attention. Most also have a colored marking of some sort on their face, although some only gain these markings upon the release of their Zanpakutō.
Physiology: It is theorized Arrancar share not only the powers of Shinigami, but also their anatomy.

Estigma: the pattern on an Arrancar's face. It is potentially the remaining part of a mask and is unique to each individual. The pattern may appear when performing Resurrección for some Arrancar.
Hole: one of the most distinctive characteristics of an Arrancar is the hole in their body. It is said to represent the lack of a heart that is difficult to fill.

Zanpakutō: The Arrancar seal the nuclei of their abilities within the form of a sword. It is entirely different from what Shinigami use. When they release their Zanpakutō's seal, they unleash their true power and their true form. The combat efficiency of an Arrancar with a released Zanpakutō is increased several times over. Therefore, an Arrancar's release of their Zanpakutō is merely a temporary restoration to their former selves, granting them any powers their Hollow form possesses. The act of release is called Resurrección (帰刃 (レスレクシオン), Resurekushion; Spanish for "Resurrection", Japanese for "Returning Blade"), which is activated with a command phrase followed by the name of the sword. An Espada's Resurrección is claimed to be different from that of a normal Arrancar.