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.

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.

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, as is the case with Nel Tu and her Hollow companions. They are at least partly capable of camaraderie and loyalty, as seen with Grimmjow Jaegerjaquez and his companions while they were still Hollows; Grimmjow's subordinates voluntarily sacrificed parts of their bodies for the sake of Grimmjow's growth.

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.

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It has been revealed 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.

Hollow get their strength and grow in Experience by devouring souls and cannibalizing other Hollow; it's not simply a factor of strength, either, as Hollow that don't feast on souls eventually grow weak. Hollow in general share common abilities such as Acidic Touch and the Garganta technique- which allows them to move between Hueco Mundo and the other worlds- but they also retain their own special abilities which is what leveling up your Hollow is focused around. These are aptly named "Mask Techniques" ranging from literally anything to anything else; whatever you can come up with, though abilities tend to tie into each other in either theme or execution.

The ranks of the Hollow go as such and are detailed below.

All abilities can be found in the Hollow Library. Higher ranks can purchase any ability that is listed as purchasable by a lower rank. Upon reaching Adjuchas and Vasto Lorde you will be expected to update your character application with your new appearance, though no other sections need to be updated should you not wish to.



The lowest rank of Hollow as far as the site is concerned; purely fodder in any sense with not much power or interest behind them. As a Demi-Hollow you are arguably the weakest of the weak with no access to customized abilities yet but having varied levels of intelligence and a few basic attacks to get you on the path. Demi-Hollow cannot leave Hueco Mundo.

Unlocked at Demi-Hollow:
Acidic Touch
Regeneration 1

Available for purchase at Demi-Hollow:
Rank Up to Rank 2
Regeneration 2



Unchained Hollow are the most common type found around the World of the Living and serve as the largest population of the Hollow race. An Unchained can start to keep up in fights against the weaker of the other races and spend most of their time eating the souls of Pluses that they find in their hunts. Unchained also get the option to start building up Mask Techniques for themselves by purchasing them. Unchained can use Garganta to travel between the World of the Living and Hueco Mundo but cannot yet get to any part of the Soul Society- not that you'd want to risk that, anyways.

Unlocked at Unchained:
Garganta


Available for purchase at Unchained:
Rank up to Rank 3
Mask Technique, 1 Slot [150 EXP cost]
Regeneration 3


Advanced Hollow are the ones known by name who cause the most trouble- special Hollow with superior intelligence and fighting skills to the lower Ranks of their race. Shinigami are often sent to kill Advanced for their more dangerous missions and some Advanced even terrorize parts of the Rukongai. An Advanced's Garganta can move them through all 3 of the worlds, though no Hollow can move closer into the Soul Society past the outer edges of the Rukongai.

Unlocked at Advanced:
Energy Shower

Available for purchase at Advanced:
Rank up to Rank 4
Mask Technique, Slot 2 [300 EXP cost]
Regeneration 4



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. Gillian, also called Menos Grande 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. 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. Gillian are rarely seen outside of the Forest of the Menos unless brought to the other worlds by strong spiritual energy drawing them.

Unlocked at Gillian:
Cero
Negacion

Available for purchase at Gillian:
Rank up to Rank 5
Arrancar Transformation* [1000 EXP cost]



Adjuchas 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 6. Appearance: Adjuchas can vary radically in appearance, anywhere from bulky humanoids to the jaguar-like form of pre-Arrancar Grimmjow Jaegerjaquez. 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. Adjuchas rarely leave Hueco Mundo due to skewing more towards cannibalizing other Hollow over devouring Pluses.

No abilities naturally unlocked at Adjuchas.

Available for purchase at Adjuchas:
Rank up to Rank 6
Arrancar Transformation* [1000 EXP cost]
Mask Technique, Slot MAX [500 EXP cost]
Regeneration Máximo
Cero Doble



Vasto Lorde 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 6. Vasto Lorde can not, except under rare circumstances, leave the desert of Hueco Mundo due to the vast spiritual energy they constantly spill out.

Abilities unlocked at Vasto Lorde:
Subjugation

Available for purchase at Vasto Lorde:
Arrancar Transformation * [1000 EXP cost]


*The Arrancar guide is seated below and has its own terms laid out for the effects of Transformation at each of the three possible ranks.

After transforming to an Arrancar state, you will be expected to update your character application with your new appearance- you will not have to re-do your history, personality or other sections should you not wish to.

Arrancar are the result of Hollows removing their masks. However, an average Hollow removing their mask would not be a problem; to hold their own, the ones removing their masks would need to be Gillian or stronger. 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). There have been Arrancar who have claimed that they gave up their Human forms in order to obtain enormous power. A number of Arrancar have tried to conceal the remnants of their past whilst 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. 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- roughly every Arrancar has their Hollow hole in a different place.

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, which is activated with a command phrase followed by the name of the sword.

While most of the Arrancar either develop or retain their own personality traits, the majority of Arrancar appear to be similarly cold, cruel, ambitious, impatient, selfish, overconfident, ruthless, arrogant, impulsive, brutal, relentless, battle-hungry, overbearing, short-tempered, indifferent, and/or egotistical.

Although Arrancar are Hollows who have gained Shinigami-like powers, most still refer to themselves as Hollows.

Arrancar are the penultimate of Hollow evolution, even beating out the Vasto Lorde in terms of power. Hollow can naturally evolve into Arrancar by ripping their mask off or having it ripped off against their will, though this process is extremely dangerous and painful. The success rate of the evolution is almost nonexistent pre-Menos stage, causing most Arrancar to have either been Gillian, Adjuchas or in the rare cases Vasto Lorde when they turned.

Becoming an Arrancar seals your power in the form of a Zanpakuto which must then be released to have access to your Mask Techniques again; all of which are retained post-transformation and just unusable before Resurreccion. Arrancar also gain a single new ability slot for their Resurreccion naturally after transformation along with the Sonido, Pesquisa, Hiero and Bala skills. Arrancar can even begin creating their own Custom Cero techniques following the template while also having the option to purchase some scarier versions of the ability.

Arrancar very, very rarely leave the comfort of Hueco Mundo (particularly the fort of Las Noches). Without proper cloaking an Arrancar would be sensed by anything with spiritual connections in a hundred miles; and even then, the sheer force of their presence is enough to cause a stir of concern.

The different tiers within the Gillian Arrancar, Adjuchas Arrancar and Vasto Lorde Arrancar dynamic are listed below along with the abilities unlocked and purchasable by Arrancar.

All abilities can be found in the Hollow Library.
* Gillian Tier Arrancar are counted as a Rank 5 until purchase of Resurreccion, while Adjuchas and Vasto Lorde Arrancar are counted as Rank 6 immediately upon transformation. *


The weakest of the inner tiers of Arrancar, going through the transformation at the Gillian stage of Menos, Gillian Arrancar retain a primarily monstrous appearance. Gillian Arrancar do not start off with their Resurreccion and must purchase it, locking them out of any of their previous Mask Techniques and the general enhancement of being able to release before they do so. In comparison to the other two tiers they're significantly redundant, at least until they put some training in to bring them up to speed. They are still Arrancar, however, and have the power behind it that allow them to outclass the lower ranks of Hollow and other races. It is not entirely unheard of for a Gillian Arrancar to work themselves stronger than the other tiers but it takes time, effort, and a lot of Experience.

Unlocked at Arrancar (Gillian):
Pesquisa
Hiero 1
Bala
Sonido 1

Available for purchase at Arrancar (Gillian):
Resurreccion [800 EXP cost]
Hiero Máximo
Sonido Máximo
High-Speed Regeneration
Cero Oscuras
Gran Rey Cero


Arrancar that transformed at the Menos level of Adjuchas make up the majority of the Arrancar forces in all of Hueco Mundo; they're the most common type, but that should not lead you to thinking of them as weak or fodder. Adjuchas Arrancar can fight on even terms with stronger Ranks of every race; even Captain class Shinigami. They start with the ability to release their Resurreccion immediately upon becoming an Arrancar which allows them quick access to all of the previous Mask Techniques they had as well as the bonus ability given by their released state.

Unlocked at Arrancar (Adjuchas):
Resurreccion
Pesquisa
Hiero 1
Bala
Sonido 1

Available for purchase at Arrancar (Adjuchas):
Hiero Máximo
Sonido Máximo
High-Speed Regeneration
Cero Oscuras
Gran Rey Cero


Just as terrifying as the Vasto Lorde are to the other Ranks of Hollow, Vasto Lorde tier Arrancar are that to the entirety of the races. They're faster, better and stronger than the other two tiers naturally and while they can be overcome it would take more than luck to do so. Not only do they have immediate access to their Resurreccion, they also start with the ability to use the Gran Rey Cero; a stronger version of the Cero and unspokenly forbidden within the confines of Las Noches as its sheer power destroys everything in its path. Vasto Lorde Arrancar are incredibly rare, even rarer than the 1/1,000,000 Vasto Lorde Hollows, and so is their exclusively purchasable ability- the Resurreccion stage of Segunda Etapa, a second, stronger version of the first. Beware the Vasto Lorde Arrancar.

Unlocked at Arrancar (Vasto Lorde):
Resurreccion
Pesquisa
Hiero 1
Bala
Sonido 1
Gran Rey Cero

Available for purchase at Arrancar (Vasto Lorde):
Hiero Máximo
Sonido Máximo
High-Speed Regeneration
Cero Oscuras
Resurreccion Segunda Etapa [2000 EXP cost]