Espada

The  are the top-ranked Arrancar in Aizen's army of Arrancar and are the primary antagonists of the series.

Outline
The Espada are regarded as the strongest Arrancar in existence. At any given time, the Espada's has a nominal composition of ten members, all handpicked and branded by Aizen himself. Along with Aizen, Gin Ichimaru, and Kaname Tōsen, the Espada as a group possess comparable strength and numbers to Soul Society's Gotei 13 and its thirteen Soul Reaper Captains.

At the time of the group's introduction, the Espada consists of nine males and one female. Each Espada member is chosen for their superior combat ability and then assigned a number from 1 to 10 (1 being the strongest one) that indicates their rank and relative power level, which is tattooed somewhere on their body (Grimmjow's is on his lower back, for instance).

The Espada are given free control over the Números and may choose as many of them as they like to become their Fracción. Similar to the power gap between captains and lieutenants in the Gotei 13, the strength of the Espada far surpasses that of the average Número. Aizen himself is confident enough of his Espada's abilities to send them out on potentially hazardous missions, such as gathering information in the real world, fighting Shinigami captains inside Las Noches and Karakura Town by themselves, and gathering the Vasto Lorde.

Being Aizen's most direct subordinates (not counting Gin Ichimaru and Kaname Tōsen), the Espada are privy to several of Aizen's plans and most intimate secrets, such as his goals of destroying Karakura Town and creating the King's Key, the location of the Orb of Distortion within Las Noches, and the name and illusory abilities of his Zanpakutō. Aizen's respect for the Espada's abilities is reflected on his manner of addressing them, often referring to them as "my dear Espada" and sitting at the head of the same table with them while discussing the events around Hueco Mundo. According to Dordonii, Aizen does not think of them as mere underlings, and he wanted to take back his position as an Espada to once again be close to Aizen.

As Aaroniero Arruruerie notes, all of the Espada except him were at least adjuchas-class menos before becoming arrancar. Overall, the eight most popular members of the Espada (both past and present) are Grimmjow, Neliel, Cirucci, Ulquiorra, Nnoitra, Aaroniero, Stark, and Halibel.

History
While it is not specified when the Espada were first created as a group, it is implied that the original Espada were already in existence sometime before Aizen's defection from Soul Society and acquisition of the Hōgyoku. Since then, the composition of the Espada has changed, reflecting a change in membership and position. Before his death, Aaroniero Arruruerie was the sole member of the current Espada who was also part of the first-generation Espada. It is possible that Grimmjow is one of the oldest Espadas since most of his Fraccions are the oldest Numeros.

Former Espada
These are the Espada that have either died or left Las Noches and did not become part of the Privaron Espada.

Demotion
An Espada may be demoted from the Espada, such as Grimmjow Jeagerjaques when his left arm was cut off by Kaname Tōsen. In most cases they will be demoted to the, who are former Espada that have officially lost their rank and are assigned a three-digit number.

Privaron Espada
The Privaron (Spanish: deprived) are former Espada who have officially lost their rank and are assigned a three-digit number. Being former Espada, they are far stronger than the normal Números. They reside in Tres Cifras, which translates literally from Spanish as "three digits". As mentioned by Dordonii, these former "naturally created" Espada were rendered obsolete after Aizen began artificially creating arrancar to meet his own standards. It may be that the Privaron Espada numbers are simply their old number turned into a three digit one. (Ex. Dordonii was the 103rd and he may have been the 3rd in the original Espada)


 * Dordonii Alessandro Del Socacchio - The 103rd (Unconfirmed)
 * Cirucci Thunderwitch - The 105th (Unconfirmed)
 * Gantenbainne Mosqueda - The 107th

Devices and Technique

 * Caja Negación is used to punish Arrancar subordinates by trapping them eternally in an alternate dimension. However, should the Caja Negación be used on an Espada, the Espada will eventually break out of the alternate dimension (usually within a few hours), due to their large amount of Reiatsu.


 * Cero: Like any other Hollows, they can use this blast technique. The Espada user fires a laser blast of great, concentrated destruction.


 * is an Arrancar alternative to the Cero. The technique hardens the user's spiritual pressure and fires it like a bullet from their fist. Though somewhat weaker than a Cero blast, it moves about twenty times much faster than a Cero and can be fired at a much higher rate. This technique was first demonstrated by Wonderwice Margera against Kisuke Urahara, and elaborated upon by Yammy during the same battle.


 * Gran Rey Cero: (王虚の閃光, グラン・レイ・セロ; Spanish for "grand king zero") is a particular, very strong Cero. To perform this potent variation of the Cero, the Arrancar first draws blood from the Cero-generating appendage using his or her zanpakuto, then charges the Cero while mixing the blood with it. The result is a Cero with a much greater attack power and speed, as well as a change of color unique to the Espada. This attack was first used by Grimmjow Jeagerjaques in order to incite Ichigo Kurosaki into donning his Hollow mask. Grimmjow refers to it as "the ultimate cero", as Gran Rey Cero is apparently a result of Shinigami-Hollow hybridization (both arrancar blood and a zanpakuto is required to use this technique). Grimmjow is, to date, the only Arrancar that has ever used Gran Rey Cero and Caja Negacion on-screen.


 * is how Arrancar move to and from Hueco Mundo. Kaname Tōsen and Kisuke Urahara have also demonstrated the ability to use the technique. It literally tears open the dimensional fabric separating the worlds, revealing a tunnel of whirling, torrential energy that must be focused and solidified to create a discernible pathway.


 * refers to the hardened skin of the Arrancar, which is a result of their compressed spiritual power. While their skin is strong enough to block even released Zanpakutō bare-handed, it is by no means impenetrable. Stronger Arrancar have proportionally stronger skin. Nnoitra Jiruga claims his Hierro is toughest amongst the Espada.


 * is the Arrancar equivalent of the Shinigami ability to sense Spiritual Pressure. It functions similar to a sonar. Using pesquisa requires most Espada to enter a meditative state; however, Nnoitra Jiruga has a variation of this technique that involves placing his fingers to the ground to determine an opponent's approximate location as well as the amount of Spiritual Pressure an opponent has.
 * is the Arrancar equivalent of the Shinigami flash steps and the Quincy Hirenkyaku; it allows the user to travel at incredibly high speeds for short distances. Use of Sonído is punctuated by a brief static sound, in contrast to the "swish" sound used for Flash Steps. Zommari Leroux claims that his Sonído is the fastest amongst the Espada.

Shinigami Counterparts
Several of the Espada are very similar to certain shinigami by either their roles, personalities, abilities, or relative power level. However, they're not exactly the same, as they also have different traits, personalities, power, roles, and abilities.


 * Stark - Shunsui Kyōraku: are lazy, laid-back, easy-going, honorable, bear similar facial features, and are powerful combatants.
 * Barragan Luisenbarn - Shigekuni Yamamoto-Genryūsai: are old and have a measure of authority, but unlike General Yamamoto, who is humble, self-assured, and powerful, Barragan is arrogant, foolhardy, boastful, and egotistical, as all six of his Fraccion call him "God/King".
 * Halibel - Soifon: are calm, reserved, loyal, and analytical. However, unlike Soifon, Halibel actually shows some concern over her opponents, whereas Soifon cruelly and inconsiderately tends to eliminate everyone that defies the Soul Society, regardless of their intentions.
 * Ulquiorra Schiffer
 * Tōshirō Hitsugaya: both said to be cold to others. Unlike Tōshirō, Ulquiorra is indifferent, brooding, powerful, depressed, and young.
 * Byakuya Kuchiki : Both are respectful of the law, quiet, loyal, and obedient.
 * Nnoitra Jiruga - Kenpachi Zaraki: use brute force in combat, wear eyepatches, and have an overly-violent lust for battle. However, unlike Kenpachi, Nnoitra is a sexist lecher and calls Orihime Inoue "pet-sama".
 * Grimmjow Jeagerjaques - Ichigo Kurosaki: are short-tempered, stubborn, reckless, rude, impulsive, persistent, resourceful, analytical, have an apparent habit of cheating death more than once, and are equally powerful combatants with a twisted sense of honor. However, unlike Ichigo, who fights for his friends, allies, and family, Grimmjow fights for his very own benefits, and does not like being look down by others.
 * Zommari LeRoux - Byakuya Kuchiki: use speed in their combat, sonído and shunpo respectively, and are generally silent, calm, somewhat overconfident, and have a small measure of pride, often refusing to accept defeat. However, unlike Byakuya, Zommari is boastful, impatient, and forceful.
 * Szayel Aporro Granz - Mayuri Kurotsuchi: are scientists and are cruel to both their enemies and their allies/minions. However, unlike Mayuri, Szayel tends to think highly and condescendingly of himself, and wishes to see all non-Hollows to be totally wiped out of existence.
 * Aaroniero Arruruerie - Jūshirō Ukitake: opposites, both dealing with Rukia Kuchiki.
 * Yammy - Sajin Komamura: are the biggest in their groups and use pure strength. However, unlike Sajin, Yammy is somewhat oafish and arrogant.
 * Neliel Tu Oderschvank - Retsu Unohana: are healers and are both disliked by the "warrior" of their rank such as 11th Division dislikes the 4th Division, whereas Nnoitra dislikes Neliel, but the class of both Neliel and Retsu are not exactly the same. Neliel being a former Espada, while Retsu is still a Captain of the Gotei 13. Also, while Neliel Tu was transformed into a kid by Szayel Aporro Granz, Retsu Unohana stays at the same appearance.

Trivia

 * Interestingly enough, Yammy introduces himself as "Espada Diez, Yammy!" (Espada 10, Yammy! in Spanish) when he fights Captain Hitsugaya during their mission to kidnap Orihime Inoue, whereas all other Espada introduce themself with XXth numbers. This may be a mistake on Tite Kubo's part or Yammy is just a special case.
 * Following the pattern set by the other Espada, Yammy's title should be "Décima Espada" (literally "10th Sword" in Spanish).


 * "Privaron Espada" literally means "they deprived the swords" in Spanish. "They" could refer to Aizen and the current Espada.
 * The Espada's titles are all the Spanish words for the ordinal of their rank (eg., Sexta means "sixth" in Spanish).
 * Curiously, all of the (revealed) titles are in the feminine form. Nnoitra and Aaroniero are exceptions; their titles are in the masculine form.


 * The tattoos indicating the Espadas' position doesn't seem to be permanent. Example: During the flashback, Nnoitra had his postion as the 8th Espada tattooed on his tongue. However, when he revealed his current position as the 5th Espada to Ichigo, the number 5 has replaced the previous number 8. This might be possible as Aizen is constantly artificially creating arrancars to meet higher standards, and this will be convenient for him to demote current Espadas if those tattoos can be erased. It might be possible for the Privaron Espadas to not reveal their tattoos as their previous rank to their enemies because they might be already erased. Nel is an exception to still have her tattoo despite not being an Espada as she was not demoted, rather ambused by Nnoitra and Szayel Aporro.
 * Barragan, Zommari and Szayel Aporro are the only Espada who have not revealed their tattoos.