Espada (Gravity Force)

The Espada (十刃, (エスパーダ), Esupāda; Spanish for "sword", Japanese for "ten blades") were once the top-ranked Arrancar in Aizen's army of hollow-shinigami hybrids, they are now the most powerful Shinigami-Hollow hybrids under G's command. They are still the main rivals of the Gotei 13. G himself has commented that the espada under his command are stronger then the old ones.

Outline
The Espada are regarded as the most powerful Shinigami-Hollow hybrids in the spiritual world. At any given time, the Espada, like it's predecessor, has a nominal composition of ten members, all hand-picked and branded by Ulquiorra Cifer, their arrancar leader. At the time of the group's introduction, the Espada consists of eight males and two female. Each Espada member is chosen for their superior combat ability, and then assigned a number from 0 to 9 (0 presumably being the strongest) that indicates their rank and relative power level, which is tattooed somewhere on their body.

The Espada are given free control over the lower less complete arrancar in Hueco Mundo and may choose as many of them as they like to become their Fracción, just like with Aizen's Espada. Similar to the power gap between captains and lieutenants in the Gotei 13, the strength of the Espada far surpasses that of the average Fracción.

Their immense amount of power and leadership status among the ranks also grants each Espada the authority to exert command over most other hollows or arrancar within their territory. Unlike their former Gotei 13 comrades, there seems to be a sort of hierarchy among the Espada; a higher-ranked member apparently can give orders to lower-ranked members. Various missions usually involve one or more Espada operating together, with the most senior member exercising command over the others; typical, non-combat missions, such as searching for the zanpakuto Muramasa and gathering pre-invasion data in the Soul Society, and the human world, include a senior Espada and a lower-ranked one being sent out in pairs. While the lower-ranked members usually have little restraint in taking their own initiative (thus exceeding their orders), higher-ranked members usually stick to the mission, and are often the first to bail the others out of trouble, because, they wish to "prevent the Espada from losing one of their own". G allows his Espada to wear whatever they want. Like the captains, G's Espada have limit releases and the top 6 Espada aren't allowed to release their Zanpakuto within Las Noches as it might damage a part or the whole Las Noches itself.

History
While it is not specified when the Espada were first brought together 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, both in membership and position. As far as what kind of species have joined their ranks, only three members of the current Espada were Captain-class Shinigami, the others being Lieutenant or lower, so Espada of the past have more prominently ascended from hollows and arrancar. After Aizen was killed by G, his Arrancar Comrades became the new Espada.

Current Espada
These Espada are only relevant to Gravity Force 's stories and story arcs.

Former Espada

 * Tsukai no Yumeuranai (Primera; defected after being ostracized by his fellow Espada)
 * Riza Prodito (Quinto; essence infused with a Shinigami. Determined a Rogue)
 * Malla (Segunda; met up with the Scarlet Alliance and decided to fight for a bigger cause)

Demotion
An Espada may be demoted from the group either when they lose strength or cease to be useful. In most cases, they will be demoted to the Privaron Espada (十刃落ち (プリバロン・エスパーダ), puribaron esupāda; Spanish for "Deprived Sword", Japanese for "Ten Fallen Blades"), who are former Espada that have officially lost their rank and are assigned a three-digit number.

Privaron Espada
The Privaron Espada 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.

Previous Espada Groups

 * Aizen's Espada
 * Aizen's Apprentice's Espada