Espada

Ten Arrancar of extraordinary strength form this elite, each marked with a numbered tattoo somewhere on the body, the digit running from zero up to nine. Fewer digits mean greater spiritual power, so the lowest numbers belong to the mightiest. As a group, together with Aizen, Gin Ichimaru, and Kaname Tōsen, they rival the assembled captains of the Gotei 13, and their rank grants them authority over the lesser forces of Las Noches, from the Números to the Exequias to their own hand-picked Fracción.

Being Aizen's closest servants apart from Gin and Tōsen, the ten are trusted with his deepest secrets, including his designs on the Ōken and the whereabouts of the Hōgyoku. A pecking order runs through their own ranks, letting higher members command lower ones on shared missions. Strict rules govern their conduct inside the fortress: those ranked fourth or above may not release their Zanpakutō there, and none may unleash a Gran Rey Cero, since either could bring Las Noches down. An Arrancar who loses a limb can be stripped of the rank, though a demoted one may reclaim it by killing whoever took their place, as Grimmjow Jaegerjaquez does.

Every seat governs a distinct form of death, one of the ways mortals meet their end, and that theme shapes the holder's powers, outlook, and very reason for being. Coyote Starrk carries solitude, so overwhelming as a Hollow that he split himself in two to escape the loneliness. Baraggan Louisenbairn rules old age, his powers rotting and aging whatever they touch, and he ironically perishes to his own decay. Tier Harribel embodies sacrifice, Ulquiorra Cifer nihility, Nnoitra Gilga despair, Grimmjow destruction, Zommari Rureaux intoxication, Szayelaporro Granz madness, Aaroniero Arruruerie greed, and Yammy Llargo rage.

Aizen dispatches his Espada on dangerous errands, from gathering intelligence in the living world to fighting captains alone, treating them as instruments he feels no grief in losing. Most fall during his war against Soul Society. In the aftermath Harribel takes the throne of Hueco Mundo, only to be captured by Yhwach when the Wandenreich claims the realm, while Grimmjow survives and later throws in with Ichigo against that same empire.

The roster spans Yammy at zero and again at ten, Starrk paired with Lilynette Gingerbuck as the Primera, Baraggan as the Segunda, and Harribel as the Tres, a seat once held by Nelliel Tu Odelschwanck. Ulquiorra ranks fourth, Nnoitra fifth, Grimmjow sixth after wresting the number back from Luppi Antenor, Zommari seventh, Szayelaporro eighth, and Aaroniero ninth. Aaroniero stands out as the sole survivor of the original generation and the only Gillian-stock Arrancar to reach the group, most of the rest having been Vasto Lorde.

Cast-off Espada who lose their strength or usefulness are demoted to the Privaron Espada, former members given three-digit numbers who dwell in the Tres Cifras; Dordoni Alessandro Del Socaccio, Cirucci Sanderwicci, and Gantenbainne Mosqueda are among them. Kubo has noted that the earliest Espada, formed before Aizen's arrival, numbered only seven and were themed after the seven deadly sins.