Seilah

Seilah (セイラ Seira) is an Etherious of the Dark Guild Tartaros and its team: the Nine Demon Gates.

Appearance
Seilah's appearance is that of a woman, with large breasts and 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. Meanwhile, 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, collected woman who has a habit of making allusions to the structure of books in her speech, however, like all the other true Demons of Tartaros, she is incredibly cold and calculating, as well as extremely merciless, forcing, without hesitation, Elfman Strauss to attack his sister Lisanna, and then proceed to use her as a hostage so that he destroys the Fairy Tail Guild on Tartaros' behalf, even smirking and blushing upon seeing the apparent realization of her plans completed with the guild buildings explosive destruction. She is also extremely loyal to Kyôka, referring to her with the honorific suffix "-sama", and engaging in implied sexual behaviors with her. Her admiration and devotion to Kyôka goes very far, as after realizing that her plan to destroy Fairy Tail ended up putting Tartaros at a disadvantage and her being made a fool of in front of her, she angrily sought vengeance against Mirajane, as she was Elfman's sister. Lastly, her loyalty does not rest solely upon Kyôka, she is also very loyal to Tartaros and the innate desire of the Etherious race (to kill Zeref), and thus endangered her own life by giving Kyôka the remainder of her Curse Power so that she, as the last member of the Nine Demon Gates, could achieve Tartaros' goal of "returning to their creator".

Tartaros arc
Seilah gathers with the other members of the Nine Demon Gates at their guild headquarters. Upon the arrival of Silver and Kyôka, but noting the absence of two of their members, the group moves to show the humans the power of the underworld as brought forth by the Nine Demon Gates.

Noting their mission to assassinate the Magic Council, a member named Ezel expresses his wish for Kyôka to allow him to be the next to do so. Hearing this, Seilah tells him that there is a proper order in which things need to be done. Seilah then heads out and joins the hunting of the Magic Councilors, arriving to Yuri's home. After taking control of Yuri's body to destroy the Lacrima in Lisanna's possession, sighing, Seilah admits to herself that expecting her Curse to function particularity well was a mistake, whilst reading the book in her hands. When asked by Elfman and Lisanna to reveal her motives, Seilah simply rises to her feet and states that she merely helped Yuri reach the gates of Hell. Subsequently, she comments on how unfitting the stories humans write are for Demons, taking control of Elfman's body at the same time; forcing him to strangle Lisanna. Elfman asks her to cease her actions, with Seilah informing him that in a Demon's story, there is no such thing as mercy. As she continues to force Elfman into harming his sister, the Fairy Tail Mage tearfully begs her to stop. Hearing his request, Seilah notes that when humans ask Demons for something, it is only when they are selling their soul to them, causing her to inquire as to whether such is what Elfman is doing.

Knowing that it is, Seilah takes Lisanna from Elfman and frees him from her control. With him as her slave and Lisanna her captive, Seilah tells the Fairy Tail Mage to return to his guild with a Lacrima she provides and plant it there. Asked what it is, she reveals it to be an ultra-concentrated ether light sphere, one which is approximately 500 times as powerful as Jupiter and will destroy the guild. Shocked, Elfman claims he cannot do such a thing but Seilah replies that he can and will as her Macro is absolute.

Some time later, Seilah returns to the Tartaros headquarters, meeting with Kyôka in her chambers. Approaching the woman, who is relaxing on a sofa, Seilah inquires as to whether they have discovered the identities of those linked to Face: when Kyôka replies that thanks to Crawford Seam they have, Seilah states that they can finally stop their pointless killings. Remarking that Face is a fearsome weapon, Seilah asks if they shall locate Jellal -the final link- soon, with Kyôka believing the recently captured Erza will soon spill his location. As Kyôka comments on both the women's abilities to make people talk, she states that something needs to be done to stop Fairy Tail from intervening in their plans once more, with Seilah stating she had something in mind. Appreciative of her efforts, Kyôka comments on not having "taken care" of Seilah for an extended period of time. Seilah is then later seen laying in bed, as a possessed Elfman returns to the Fairy Tail Guild.

Shortly after Face awaken and Tartaros' building begins to shake, Seilah heads to Kyôka and Franmalth's current location, reassuring the worried Demons that Fairy Tail will not intervene; their "story" shall soon reach its end. Standing next to Kyôka as they gaze at the Fairy Tail guild from a Lacrima-Vision, Seilah smirks as she advises the latter to pay close attention to the proceedings. Before long, the building home to the fairies bursts up into flames and Seilah tells Kyôka that it is as she has seen, earning her the woman's congratulations. However, as Kyôka begins to give them orders, Franmalth discovers many sources of Magic Power approaching Cube, prompting Seilah to display Undercube, where she notices Fairy Tail's three Exceeds approaching Cube while holding cards. Upon hearing that the cards contain all the Mages of Fairy Tail, Seilah goes wide-eyed in shock and blames herself for Tartaros' current predicament.

Soon after, Seilah happens upon the reunion of Mirajane and Lisanna, whereupon she hears Lisanna describe their ordeal. Seilah, however, corrects her assertions by stating that Elfman was not one of the Fairy Tail members they captured. Instantly recognized, Seilah reveals that Elfman was ordered to destroy the guild building, he was successful as the structure was blown up but failed due to the fact that nobody died. As a result, she was embarrassed in front of Kyôka and therefore wishes to make Mirajane pay the price. Seilah then quickly engages Mirajane in combat and overwhelms the woman with books alone, remaining relatively unharmed despite the woman using her Satan Soul; Seilah continues her assault, eventually pushing Mirajane completely onto the defensive.

Seilah eventually temporarily ceases her assault and asks Mirajane what she is, as her Macro has no effect on her; she states that with her Macro, because she can remotely resume control over something she has controlled before, she can make Elfman harm himself. However, before she can do so, a mutilated Ezel appears in the tank next to Seilah and demands that she revive him, which she refuses to do as she is in the middle of a battle. After the fact, though, Lamy explains that they're in Hell's Core and that it is Tartaros' respawn point, which prompts Seilah to chastise her. Then, when Mirajane states that her new objective is to destroy Hell's Core, Seilah wonders aloud if she can; when Mirajane does, by taking over the tentacles inside the tanks, Seilah realizes that the reason her Macro doesn't work on Mirajane is because of her Satan Soul. As neither woman can use their abilities on the other, they are forced to rely on physical combat, but before they can clash, Seilah uses her Macro on herself to release her limiter. Going forth, she strikes Mirajane faster than she can react before releasing an intense magical blast from her palm that not only obliterates what's left of Hell's Core, but greatly harms Mirajane, Lamy and Lisanna, as well as forcing the former to exit her recently-entered Sitri.

Continuing her assault on Mirajane, Seilah charges towards the Fairy Tail Mage and tackles her across the room. As Mirajane attempts to use her Take Over on the Demon once more, Seilah reminds her that it is useless, and further commands her body to tear apart the woman in front of her. After brutally slashing away at Mirajane's body, Seilah is then surprised when the Mage grabs hold of her leg, and feels herself weakening. Recognizing the danger Mirajane presents, Seilah releases her Demon Eye in a desperate attempt to erase the Mage, but before she can finish Mirajane off, Elfman appears from above and crashes into Seilah's body, instantly incapacitating her and ending the fight.

Seilah lays unconscious until the clones of Lamy attack; she awakens and then sneaks away in the ensuing chaos. She then, with Kyôka at her side, makes her way to the control room, where she uses her Macro to control the chairman's corpse in place of the deceased Keyes. Seeing Erza, Minerva, the Exceeds and Franmalth arrive, she uses her Curse to restrict everyone's movements and force them to choke themselves; Seilah reveals herself to be responsible for the chairman's movements, though she makes it apparent that she's not as skilled at corpse control as Keyes, and then tells everyone that they're going to die where they stand. However, Seilah is then taken out by Mirajane, who she curses for her meddling. Apologizing to Kyôka for her failure, she is reassured that she did well, as Face is now only minutes from activating. Proceeding to give Kyôka the remainder of her Curse Power, Seilah asks her to return them all to Zeref, as she is the last Nine Demon Gate, and then begs for her to win. With no more power left, Seilah merely lies on the ground, unconscious, as Kyôka and Erza fight.

Some time after, Seilah is found in a near-death state by Mirajane, who performs Take Over on her, which not only saves her life, but also gives Mirajane her appearance and powers in the form of Satan Soul: Mirajane Seilah.

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.
 * Limiter Release (制限解除, リミッターかいじょ, Rimittā Kaijo): After turning her Macro ability upon herself, Seilah is able to remove her own self-imposed limits to enter her Etherious Form.

Etherious Form (エーテリアス フォーム Ēteriasu Fōmu): Seilah, like the rest of her race, has shown the ability to enter an Etherious Form, however in a rather unconventional way: she must first turn her Macro upon herself and order her own limits away. 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.

Quotes

 * (To herself) "The stories written by humans are boring. I shall write my own story, the story of the demons."
 * (To Elfman Strauss and Lisanna Strauss) "In a Demon's story... there's no such thing as mercy."
 * (To Fairy Tail via Elfman Strauss) "Fairies should be broken from the inside out, wouldn't you agree?"

Battles & Events

 * Mirajane Strauss & Lisanna Strauss vs. Seilah & Lamy

Trivia

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