The Espada are without a doubt Aizen's most powerful servants, and generally serve as the leaders of some of his forces. They are ranked according to their reiatsu level, though this does not necessarily mean that a higher-ranking Espada is truly stronger than a lower-ranking one (despite it being usually the case): Yammy Llargo, despite being the Cero Espada upon his release, is still considered to be the weakest of the group due to his stupidity and general lack of combat skills. Members are replaceable, and it is possible to be promoted/demoted from one rank to another or be removed from the Espada altogether.
Due to their ranking, the Espada possess exclusive several abilities and privileges, such as command over the Numeros and the right to take any lower-ranking Arrancar (minus other Espada) as their subordinates, or Fraccion. They can also set up their own headquarters, from which they can indulge in their own habits until they are summoned by Aizen. They also possess a unique Cero, the Gran Rey Cero, that is more powerful than any other, though they are forbidden by Aizen from using it within Las Noches.
The four strongest Espada - Ulquiorra Cifer, Tia Harribel, Baraggan Luisenbarn, and Coyote Starrk - are forbidden to release their Zanpakuto within Las Noches because the reiatsu release alone would destroy the base, though they can apparently release it without fear while on the roof of Las Noches.
The creation of the Espada has long been one of Aizen's most important preoccupations. While it is not specified when the Espada were first brought together as a group, the original Espada were already in existence sometime before Aizen's defection from the Soul Society and acquisition of the Hogyoku. Since then, the composition of the Espada has changed, both in membership and position.
At some point in the past Nnoitra Jiruga was the 8th Espada with Nelliel as the 3rd Espada and Szayel Aporro Granz was not a member at all. During this time Aizen frequently sent the Espada out to search for the Vasto Lorde-class Menos.
|Rank||Name||Zanpakuto||Tattoo Location||Aspect of Death|
|0||Yammy Llargo (Post-Release)||Ira||Left Shoulder||Rage|
|1st||Coyote Starrk & Lilynette Gingerbuck (Post-Release)||Los Lobos||Back Side of Left Hand||Solitude|
|2nd||Baraggan Luisenbarn||Arrogante||Unknown||Aging (Time)|
|3rd||Nelliel Tu Odelschwanck||Gamuza||Mid Back||Unknown|
|3rd||Tia Harribel||Tiburon||Left side of right breast||Sacrifice|
|4th||Ulquiorra Cifer||Murcielago||Left pectoral muscle||Emptiness|
|5th||Nnoitra Jiruga||Santa Teresa||Tongue||Despair|
|6th||Luppi Antenor||Trepadora||Right Hip||Unknown|
|6th||Grimmjow Jaegerjaquez||Pantera||Right side, mid back||Destruction|
|8th||Szayel Aporro Granz||Fornicaras||Unknown||Madness|
|9th||Aaroniero Arruruerie||Glotoneria||Top head: 3/4 of head|
Bottom head: 1/2 of head
An Espada may lose his/her rank if he/she is somehow weakened or displeases Aizen. If this happens, that Arrancar's Espada tattoo will be somehow removed (or concealed), and he/she could either become a Numeros, a Privaron Espada, or maybe even a Fraccion.
The Privaron Espada (Spanish for "Deprived Sword") are natural Arrancar who were once members of the Espada but were demoted and replaced by the artificially created ones. Their authority, if they possess any at all, over the Numeros is unclear, but nonetheless, they tend to serve as outer guards to Las Noches and have their own personal headquarters, so they likely possess some level of authority over lower-echelon Arrancar or Hollows.
|Rank||Name||Zanpakutō||Tattoo Location||Aspect of Death|
|103rd||Dordoni Alessandro Del Socaccio||Giralda||Unknown||Unknown|