Hollow to Espada

Overview:

In the Bleach universe, one of the planes of existence is the desert-like realm of Hueco Mundo (虚圏(ウェコムンド), Weko Mundo, Spanish for "Hollow World", Japanese for "Hollow Range") where the Hollows thrive on spirit energy. A Hollow is the result of a departed soul (known as a Plus, or a Whole in the English translation) being corrupted into a malevolent incarnation of itself. When a Whole has many regrets or a strong emotional connection to a location or person, their Chain of Fate (因果の鎖, inga no kusari?), which links their soul to their body, becomes attached to the emotionally important object or person. After some time, these souls become Hollows from either their souls becoming corrupt or the Chain of Fate corrodes. The Hollows that appear in the land of the living have a strong desire to feed on human souls in an attempt to fill the void left in their hearts, which is why they are said to first attack the people that they had loved the most in their past lives. Hollows generally have a full recollection of their lives as humans. Hollows have very varied character designs, though most are designed with a monster-like appearance, a skull-like mask and a large hole somewhere through their body.

There are two main duties of ordinary Soul Reapers: to perform a ritual known as a soul burial (魂葬 (こんそう), konsō?) on Wholes before they become hollows, and to slay hollows to purify their souls of all sins committed while in that form, so that they become Wholes once again. When either of these duties are fulfilled, the Whole goes to Soul Society. If a hollow committed grave sins as a human, their destruction opens the gates of the underworld, where they are dragged to their punishment. It is also possible for a spirit to awaken their dormant abilities of a Soul Reaper to avoid turning into a hollow.

There are also special case Hollows like menos and arrancar, who gain access to unique skills and abilities, fueled by the souls they have consumed. The most common of these abilities is cero (虚閃（セロ）, sero?, Japanese for "hollow flash," Spanish for "zero," called both "cero" and "doom cero" in the Viz manga), a high-powered energy blast that can be fired from various body parts, such as the mouth or hand.

Menos

Menos (メノス, menosu, Spanish for "minus" or "less") hollows have an unusually strong thirst for souls, which leads them to consume other Hollows and evolve into a stronger state of being. Within the Menos, there are three levels of evolution, each with superior strength, speed, and intelligence compared to its previous form. The first of these is the Gillian (最下大虚（ギリアン）, girian, Japanese for "least of the great hollows", spanish for "Countless Creature"), or Menos Grande (大虚 (メノスグランデ, menosu gurande?, Japanese for "Great Hollow", spanish for "Great Minus") which normally reside within the Menos Forest located below the desert surface of Hueco Mundo. The Gillans are powerful giants that are born when countless cannibalistic Hollows gather into a feeding frenzy until they are mingled into a single form with very little intelligence and no individuality as a result of being a collective of hundreds of Hollows. If one of the Hollows that now make up the Gillian retains its consciousness, it dominates the entire entity and, after eating enough Hollows (including other Menos), eventually evolves into an Adjuchas (中級大虚（アジューカス）, ajūkasu, Japanese for "intermediate great hollow").

Semihuman or animal-like in nature and smaller in size, the Adjuchas are able to keep up with Soul Reapers in a fight yet must continue eating Hollows or they permanently regress back to Gillians with their mind destroyed in the process. There are some cases where Adjuchas can halt regression if another Hollow devours even a small piece of their bodies, as well as cases where some Adjuchas can command groups of Gillians. The few Adjuchas that transcend their limits become the Vasto Lordes (最上大虚（ヴァストローデ）, vasuto rōde, Japanese for "great king of the hollows", Spanish for "vast", pseudo-Spanish "lord"), the most human-like of Hollows whose power equals to that of a Soul Reaper captain.

Arrancar

Arrancar (破面（アランカル）, arankaru, Japanese for "broken mask", Spanish for "to tear off") are hollows that have had their masks almost completely removed and—through this process—gained the powers of a Soul Reaper, a more humanoid appearance, as well as strength, speed, and intelligence beyond the level of a normal hollow.

In addition to those improvements, arrancar also gain hierro (鋼皮 (イエロ), iero?, Japanese for "steel skin", Spanish for "iron"), skin so hard that it allows them to fight against sword-wielding opponents bare-handed, but is by no means impenetrable. In order to travel at extremely high speeds across short distances, arrancar use a technique known as sonido (響転（ソニード）, sonīdo, Japanese for "transfer effects", Spanish for "sound"). Stronger arrancar have been shown to possess proportionally harder hierro and faster sonido, among other abilities, either unique or based on common techniques, such as the several existing variants of cero.

Like Soul Reapers, arrancar possess zanpakutō (斬魄刀?, lit. soul-cutting sword). Unlike Soul Reapers, whose zanpakutō are manifestations of their owner's soul, an Arrancar's zanpakutō is a manifestation of their power as a normal Hollow. With occasional exceptions, the Arrancars' zanpakutō resembles a regular sword in its sealed state. When released through a process called resurrección (帰刃（レスレクシオン）, resurekushion?, Japanese for "returning blade," Spanish for "resurrection"), part of their original hollow form is restored, changing their appearance, giving them greater strength, and granting them access to their original abilities. In some cases, an Arrcanar can discard elements of his/her released form, ripping off pieces of the armor to better focus their power. However, this results in the Arrancar losing that attribute permanently like ripping off one's own limb.

Espada~

The Espada (十刃（エスパーダ）, Esupāda, Japanese for "ten blades," Spanish for "sword") are the ten strongest Arrancar the army, and each of them represents an aspect of death. There are based at Las Noches (虚夜宮（ラス・ノーチェス), Rasu Nōchesu?, Japanese for "Hollow Night Palace," Spanish for "The Nights"), which was originally Barragan's domain until Aizen took it and remodeled it into a palace. They are ranked in order of their strength and have their respective number tattooed somewhere on their body as proof of their superiority. While it was originally thought that the Espada were ranked from 1 to 10, with 1 the strongest and 10 the weakest, they are in truth ranked 0 through 9. The Espada are also allowed to choose any ordinary Arrancar and have them appointed as their direct subordinates, referred to as Fracción (従属官(フラシオン), furashion?, Japanese for "subordinate official," Spanish for "fraction"). Each Espada also possesses a Caja Negacion, a cube like item meant to permanentally seal away any Fracción as a punishment. But stronger Espada can escape from the Caja Negacion's subspace over time.

Privaron Espada

The Privaron Espada (十刃落ち（プリバロン・エスパーダ）, Puribaron Esupāda?, Japanese for "fallen from the ten blades," Spanish for "deprived sword", literally "they deprived the sword") are Arrancar that were once Espada yet were demoted out of either being a disgrace to the group or replaced by the artificially-created Arrancar Aizen created with the Hōgyoku. They have received a three-digit number in order to separate them from the regular Arrancar since their power is still far above average.