An Arrancar is a Hollow that has removed its mask and gained Shinigami powers. The name "Arrancar" is a Spanish verb meaning "to remove" or "to rip off," a reference to an arrancar's removal of its Hollow mask.

Shinigamification is the process of turning a Hollow in an Arrancar. Few Hollows have the ability to remove their own mask and doing so would create a minimal change in their power and appearance. But Aizen Sosuke is able to artificially create an arrancar using the Hogyoku or Orb of Distortion.

The process of artificially creating an Arrancar using the Hogyoku unlocks the Hollows ability compared to the natural process of shinigamification.

◊ Espada ( spanish for sword ) the most powerful arrancar in Aizen's army. Each Espada is given a Number (from 0 to 9) as their rank when they are created. That Number is relative to the Espada's combat ability and power level. This number is tattoed somewhere on their body (Noitoras' on his tongue, for example).Espadas are given suburdinates called fraccion.

Aizen being the most direct subordinates (not counting gin Ichimaru and Kaname Tōsen), the sword is privy to some of the Aizen plans and most intimate secrets, as his goal of destroying Karakura Town and King's creating key, the location of Hōgyoku within Las Noches, and the true name and his ability Zanpakutō. Aizen's respect for the sword skills are reflected in his manner of addressing them, often referring to them as "my dear sword" and sitting on the heads of the same table with them, while discussing the events around Hueco Mundo. By Dordonii, Aizen not think of them as underlings, and he wants to get back his position as a sword again be near Aizen. Though it all, Aizen is not at all distressed to death by sword and calmly congratulates the intruders in Las Noches for their victories against the sword as he leaves for Karakura Town. Dordonii's disillusioned view of Aizen is comparable to Momo Hinamori's.

◊ Privaron Espada ( spanish for Deprived Sword ) Former Espada who lost their ranks because of the arrival of more powerful Espada Which was created by Aizen using the Hougyoku.Privaron Espada are assigned a three digit number and resides in Tres Cifras which literally translated as "three digits"

The Números are assigned a two digit number at birth from 11 to 99 to indicate their age (the number 11 is the oldest, number 99 is the youngest). The main number uniform consists of a white-collared jacket and robes held with a black ribbon. However, the uniform is customizable, giving each number a sense of individuality. The fighting ability of Números is considered superior to all other arrancar, except for swordfish (current and past). The strongest Números is selected by sword into their Fracción. Most Grimmjow's Fracción a higher number, implying that they are among the first Números created. Wonderweiss Margera appears one of the youngest and the youngest Números appear in manga.

They are responsible for dealing with intruders and Rebels in Las Noches, usually terminating as with their names. They are the equivalent of Soul Society's Onmitsukidō.

The Espadas, like many of the Números, seemed to have a level of control over Exequias: Szayel Aporro Granz ordered them to kill the intruders and take the bodies of their defeated opponents. Then Szayel summoned the Exequias proceeded to act under Rudobōn's command.

Rudobōn shows Rukia that the special abilities of his Zanpakutō, Arbola, allows him to create the underlings that have been following him. This explains why they all have identical masks and Zanpakutō. Technically, Rudobōn is the sole member of Exequias, including other members being only his creations without individuality seen so far.

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 Relatsu.

Like all other hollows, they can use this blast technique. The Espada user fires a laser blast of great, concentrated destruction. While the color of most ceros is red/crimson, several famous members of the Espada appear to have great color variations in their Cero; Ulquiorra's is green, Nnoitra's is golden yellow, and Neliel's seems to be violet or pink (as she was using Cero Doble; it is unclear if her normal Cero is a different color). As he's the only Espada to have utilized its power on-screen, Grimmjow's liberal use of Gran Rey Cero, which emits a light-blue color, also counts, though his regular cero is normally crimson.

Bala (Bara; Spanish for "bullet" Japanese for "Hollow bullet") 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 Wonderweiss Margera against Kisuke Urahara, and elaborated upon by Yammy during the same battle.

Gran Rey Cero (Spanish for "grand king zero") is a particular, very strong Cero. To do this powerful variation of Cero, the arrancar first draws blood from cero generate more with his zanpakutō, then the charges Cero while mixing the blood with it. The result is a Cero with greater power and speed of attack, as well as changing the color of the unique sword. The attack was first used by Jaegerjaquez to induce Ichigo to donning his hollow mask. Grimmjow defines them as "the ultimate cero", like the Gran Rey Cero is apparently a result of shinigami-hollow hybridization (Arrancar both blood and a zanpakutō is required to use this technique). Grimmjow is, to date, the only arrancar who ever used Gran Rey Cero and Caja Negacion on-screen.

Sonído (Sonīdo; Spanish for "sound") is the Arrancar equivalent of the shinigami Flash Step and Quincy Hirenkyaku; it allows the user to travel at incredibly high for the speed of short distances. Using the Sonído are punctuated by a brief static sound, in contrast to "swish" sound used for the Flash Step. Zommari claims he Sonído is the fastest amongst sword; rigid and Ulquiorra appear more quickly, however, that the first and Cuarta, respectively.