Seilah (Six)

Seilah (セイラ Seira) is an Etherious of the Dark Guild Tartaros and a former member of its original team: the Nine Demon Gates. However, after the initial collapse of Tartaros following its defeat at the hands of Fairy Tail, Seilah reformed the guild, both with its remaining original members, and new members, in order to bring down Fairy Tail.

Appearance
Seilah's appearance is that of a woman, with her most noticeable feature being the two large gold-looking horns protruding from the sides of her head and pointing upwards. Upon her head is a white band which separates her hair, framing her bangs from her hair below the band. Worn upon her forehead is a small circular symbol with a small dot on the inside and surrounded by several dots around the top. Tied around her neck is a small white-colored strap.

Seilah's attire consists of a very revealing beige-colored leopard-printed kimono, bearing the decorative marks on her shoulders. The kimono is wrapped around her torso with a thick, decorative yellow ribbon that ties behind her back, and her outfit is complemented by thigh-high socks that reveal her heels and toes. Upon turning her Macro ability onto herself, Seilah is able to force a transformation upon her body by commanding it to go beyond its limits. Seilah changes into a more demonic form than before, with her skin darkening and her horns growing in size. Her hair becomes much wilder, and the clothes around her torso disappears, revealing her bare chest to be covered in an intricate, symmetrical tattoo that begins at the choker around her neck, and ends at her stomach and hips. Tartaros' guild mark is printed onto her stomach, underneath a heart-shaped design in her tattoo. Her lower body significantly changes, with her legs changing into narrowed stilts that gradually widen up to her hips that now flare out into two wing-like protrusions and her feet changes into those of sharp blades.

Personality
Seilah is a calm and collected person who uses story chapter motifs in her speech. She has also displayed a cold and ruthless side to her as shown when she told Elfman that "mercy doesn't exist in the story of Demons" while forcing him to strangle Lisanna with her Curse. She is incredibly loyal, if not infatuated with Kyôka, blushing when she was praised for initially believing that she destroyed the Mages of Fairy Tail, and referring to her with honorific -sama. She also has a sense of pride as well as arrogance, shown when she planned to get revenge on Mirajane for ruining her reputation and shaming her in front of Kyôka. Following Kyôka's death at the hands of Minerva, Seilah has swore to avenge her fallen comrade, and is in the process of doing so, showing her sheer dedication to the deceased Etherious. While she retains her usual cool and collected demeanor, the mere thought of Fairy Tail makes the Demon's blood boil. She even had one of her fellow demons do her work, and infiltrate the Fairy Tail guild, Tsukisasu, with whom she has formed both a three-man team (with the young Etherious Lamy as the third member), and a trusting bond with over the past few centuries, to the extent where they respectfully refer to each other as (Seilah)-chan and (Tsuki)-sama some of the time.

Synopsis
For the actions of Seilah and Tartaros during their initial debut, please refer to her Synopsis on the official Fairy Tail wikia here

For her recent actions following the original Tartaros' defeat, its reformation under Seilah's leadership, and the introduction of new members, please refer to Operation: Restoration.

Curse and Abilities
Macro (命令, マクロ, Makuro): This Curse allows Seilah to fully control the body of her victims and manipulate them as if she was giving "orders". She has demonstrated the capacity to control both corpses and living humans, even though she stated herself that corpses subjected to her Curse do not function well. Her powers aren't solely limited to bodies, however, as Seilah has also demonstrated the ability to manipulate and suspend objects with her hands, as shown in her fight with Mirajane Strauss in her basic Satan Soul, where Seilah assaulted her with multitude of books, that levitated around her person.
 * Limit Release: After turning her Macro ability upon herself, Seilah is able to enter a form that is akin to the Etherious Form much of her race employs. The transformation is ended once Seilah is knocked unconscious.
 * Energy Blast: Seilah forms kanji circles around her hand, to which a third eye then grows on her open palm. From this point she is capable of generating an enormous blast of energy with enough destructive force to blow apart the majority of Hell's Core, the floor above it, and cause enough damage to Mirajane that she was forced out of her Satan Soul: Sitri form.
 * Demon Eyes: By releasing her power even further, Seilah is able to initiate a secondary transformation. By charging energy in her hands, two inscription-based wings form around her arms, and an eye appears on each palm. The effects of this ability remain unseen, however, as Seilah was knocked unconscious by Elfman from behind before she was able to unleash the stored energy.
 * Enhanced Speed: Seilah's speed is augmented to the point of easily surprising Mirajane, despite the Fairy Tail Mage being in her strongest Satan Soul form.
 * Flight: With the help of her ability, Seilah is shown to be able to fly at great speeds

Trivia

 * In her Limit Release, surrounding Seilah's hand are kanji, but they do not form words. They are simply symbols in a magic pattern. The kanjis meaning are concepts like "murder", "beauty", "rot", "sea", and other primal-seeming terms.