WHT IS HOLLOW........

A Hollow is a spirit that becomes an evil incarnation of itself, formed when the soul loses its Chain of Fate (因果の鎖 Inga no Kusari), the link to its physical body, and is overcome with negative emotions.

One plane of existence in the Bleach universe is the desert-like Hollow world called Hueco Mundo (虚圏（ウェコムンド） Weko Mundo, Spanish for "Hollow World," kanji translates as "Hollow Range") where the Hollows thrive on "spirit energy" as a life force. The Hollows that appear in the human world have a strong desire to feed on living souls in an attempt to fill the void in their hearts left from losing their Chains of Fate, hence the reason they are said to attack first those they had loved most in life. Hollows generally do not have recollections of their lives as humans. Hollows also have varied character designs, though most are designed with monster-like appearances, skull-like masks, and a large hole somewhere through each of their bodies, usually where their hearts used to be.

There are two main duties of the Soul Reapers regarding souls: to perform a ritual known as a soul burial (魂葬（こんそう） konsō) on normal souls before they become Hollows, and to purify the sins of Hollows so they once again become normal. When either of these duties are fulfilled, the soul goes to the Soul Society.^] If a Hollow committed grave sins as a human, its destruction opens the gates of the underworld, where it is dragged to its punishment.

There are also special case Hollows like MENOS and ARRANCARS, who gain access to unique skills and abilities, fueled by the souls they have consumed. The most common ability is Cero (虚閃（セロ） Sero^?, Spanish for "zero," kanji translates as "Hollow Flash") also called "Doom Blast" in the English manga, a high-powered energy blast that is fired from some part of the body, such as the mouth or hand.

MENOS:

 

Menos (メノス Menosu, Spanish and Portuguese for "minus" or "less") Hollows have an unusually strong thirst for souls, leading them to consume other Hollows and evolve into a stronger state of being. Within the Menos are three levels of evolution, each with superior strength, speed, and intelligence compared to its previous form.

The first level of Menos is the Gillian (最下大虚（ギリアン） Girian, kanji translates as "Least of the Great Hollows") class, they are also known as "Menos Grandes" (大虚（メノスグランデ） Menosu Gurande, Spanish and Portuguese for "less big/not as big," kanji translates as "Great Hollow"). They are considered foot soldiers to the other Menos, and normally reside within the Menos Forest located below the desert surface of Hueco Mundo. The Gillians are powerful giants, masses of countless cannibalistic Hollow identities gathered into one form, each with very little intelligence or individuality.

If one of the Hollow consciousnesses that now make up the Gillian surfaces above the others, that identity dominates the entirety, and through eating other Gillians, eventually evolves to the next level, Adjuchas (中級大虚（アジューカス） Ajūkasu, kanji translates as "Intermediate Great Hollow"). Granted with superior intelligence, Adjuchas give orders to Gillians, and are better able to do combat with Soul Reapers. Adjuchas must continue to eat Hollows to maintain their individuality or they risk regressing to their original Gillian form. There are some cases where Adjuchas will halt regression, since if a part of their bodies are eaten they shall stop evolving completely.

The very few Adjuchas that transcend their limits become Vasto Lorde (最上大虚（ヴァストローデ） Vasuto Rōde, Spanish for "complete lord," kanji translates as "Great King of the Hollows") class. They are the closest Hollows in size to humans and have power greater than that of a captain-class Soul Reaper. At one time in the story, Captain Tōshirō Hitsugaya speculates that the Soul Society "would be doomed" if their enemy Sōsuke Aizen gets at least ten Vasto Lordes under his command. It is shown in the anime that at least one of the Espadas (Tier Halibel) was a Vasto Lorde before joining the Espadas.

^ARRANCAR:

An Arrancar (破面（アランカル） Arankaru, Spanish for "to tear off," kanji translates as "broken mask") is a human-like Hollow with its Hollow mask almost completely removed. Arrancars have the powers of a Soul Reaper, including a weapon similar to a Zanpakutō, as well as strength, speed, and intelligence beyond the level of normal Hollows. In addition to these improvements, Arrancars also have hierro (鋼皮（イエロ） iero, Spanish for "iron," kanji translates as "steel skin") skin, hard enough to defend against swords to an extent. Arrancars use a technique known as sonido (響転（ソニード） sonīdo Spanish for "sound," kanji translates as "moving sound") to travel at extremely high speeds across a short distance. Stronger Arrancars have been shown to possess relatively harder hierro or faster sonido among other abilities, either unique or based on common techniques, such as the several variants of the Cero technique.

Like Soul Reapers, all Arrancars possess a Zanpakutō (斬魄刀, literally, "soul-cutting sword"). Unlike a Soul Reaper's, however, whose Zanpakutō is a manifestation of its owner's soul, an Arrancar's Zanpakutō is a manifestation of its former self. With occasional exceptions an Arrancar's 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 Spanish for "resurrection," kanji translates as "returning blade"), the sword combines with and changes the appearance of the Arrancar. In most cases of Resurrección part of the Arrancar's original Hollow form is restored and the Arrancar is granted greater strength and access to his or her original abilities. Arrancars are able to discard or remove certain elements of their released forms to better focus their powers. This results, however, in the Arrancars losing those attributes permanently, comparable to ripping off one's limb.

Arrancars become major antagonists in Bleach during the second part of the series, as they are led by Sōsuke Aizen, who uses the HOGYOKU to create and perfect the Arrancars. But after Vandenreich's conquest of Hueco Mundo, setting up the final part of the series, many of the Arrancars who survived Aizen's defeat were captured to be either drafted as soldiers or be killed. According to Tite Kubo, many of the Arrancars are named after real life architects and designers.