Satan Soul (サタンソウル Satan Sōru) is a Satan Soul Spell.
Satan Soul is a powerful spell, as well as the source of Mirajane's epithet “The Demon". Satan Soul allows her to take over the appearance, abilities and powers of a demonic being. When she activated it for the first time after two years of abstinence, she released a large Magical blast which destroyed the surrounding area. Satan Soul is initiated by seemingly covering Mirajane’s body in flat, square-shaped scales-like parts, which subsequently disappear, revealing her new appearance. Using this spell is extremely exhausting for Mirajane, so much that she cannot execute it in consecutive reprises. However, after her 3-month training in X791, she was shown to be able employ her Satan Soul: Sitri (which Erza commented on being one of her strongest) twice and her Satan Soul twice within the span of a few hours or even less, without any signs of fatigue.
Whilst using Satan Soul, Mirajane's eyes become darker and her eyelashes grow larger, with a dark, thin marking in a light zigzag-style crossing her right eye vertically; similar markings are present above her right breast and on both of her bare thighs. Her hair becomes wilder, jutting upwards and getting curlier, with the front ponytail growing longer, and her ears enlarging, extending backwards, and gaining pointed edges, bearing resemblance to those of the fictional elfs. She also gains sharp canine teeth, and her lips become covered in dark lipstick. Her forearms and hands receive noticeable changes, becoming covered in scales and each sprouting a fin-like protrusion on its outer side. She also grows a large, stocky tail seemingly made of metal plates or scales, getting smaller and smaller near its end.
Her clothing also changes, with any attire she might be wearing being replaced by a dark, skimpy one-piece suit, which reveals her arms and legs and is open on the front and the back, exposing most of her belly and wide cleavage. Such clothing has golden-colored edges taking on spiky shapes, and her similarly spiky collar is tied around the neck by a cravat tie. Her shoulders are tied in thin belts protruding from her one-piece suit, and her feet are covered by matching, high-heeled thigh-high boots, which are decorated by lighter motifs on their upper parts, taking on the shapes of jagged blades pointing downwards on the front of her legs, and on the lower parts, in correspondence to her ankles and feet. She also dons a pair of gauntlets covering the back parts of her transformed arms.
Darkness Magic (闇の魔法 Yami no Mahō): Mirajane has proven herself to be a skilled user of Darkness Magic. Using the magic as her game-changer in most of her fights. She was able to match and defeat Freed Justine's own Dark Écriture: Darkness. Mirajane has shown to be able to use this magic to enhance her physical combat capabilities, create powerful blasts, explosions, shields and even shape it into claw like tendrils capable of chasing after opponents.
- Darkness Stream: Mirajane extends her hand towards the opponent and summons forth her Magic Seal underneath her opponent, where a multitude of large tendrils composed of dark energy is formed, which surround and envelope the opponent. It was used against Freed, who evaded it, thus leaving its full effects unknown.
- Soul Extinctor: Mirajane initiates this attack by gathering energy from the surrounding area between her hands, which subsequently takes the form of a large, black globe. The globe then fires a large black-purple beam that generates a devastating explosion. This spell was strong enough to defeat Freed, who no longer had his Dark Écriture: Darkness and Dark Écriture: Wings spells active after its blast. This spell is unnamed in the manga, but it was given a name in the anime. There also seems to be a variety to it, in which the sphere, seemingly created faster, is focused around Mirajane's hands and forearms and shot in a less powerful, yet still destructive blast.
- Evil Explosion (エビル エクスプロージョン Ebiru Ekusupurōjon): Mirajane holds her hands together and a dark colored sphere gathers on her palm. When fired, it is fired from Mirajane's hand. The receding explosion is devastating. This spell was powerful enough to almost completely destroy Azuma's Tree Shield. However, he himself received little to no damage. In the manga, the spell is unnamed, but it received a name in the anime.
- Demon Blast: A large ball of dark energy is charged between Mirajane's hands, from which a dark purple beam is fired towards the target.(Unnamed)
- Satanic Blast: The user raises her hand above her head and starts charging Darkness Magic in the form of a sphere that grows larger as it charges. The user then aims her hand at the target, sending a large blast at the target that then becomes a huge pillar of Darkness Magic covering the entire area. (Unnamed)
- Dark Deflect: Focusing the incoming attack on her eye, Mirajane redirects the incoming spell, missing the intended target. (Unnamed)
- Evil Explosion (エビル エクスプロージョン Ebiru Ekusupurōjon): Using her Magic Power as a medium, Mirajane lifts a body of water, even one as big as a river, with her arms, and then starts rotating, sending the water flying towards her foe in a powerful whirlpool. This spell, which remains unnamed in the manga, was given a name in the anime.
- Evil Spark: A melee spell in which Mirajane extends both of her hands to touch the opponent, subsequently channeling electricity through them.
Flight: In this form, Mirajane is capable of sprouting a pair of wings from her back at whim, which allow her to fly. Such wings are reminiscent of a bat’s, and come with small spike-like protrusions on their upper edges.
Enhanced Durability: This form increases Mirajane's natural durability, allowing her to take multiple powerful explosions from Azuma in consecutive reprises, emerging almost unscathed and remaining active to continue the battle.
Enhanced Speed: While in this form, Mirajane's speed increases to the point where, after sprouting her wings, she could easily deliver a powerful punch to Freed, even with the help of his own wings and a large distance between them, before he could react. During her fight with Azuma, she could similarly deliver a powerful kick into his stomach before he had the chance to react.
Immense Strength: When employing her demonic powers, Mirajane's strength is increased to the point where she can easily break through solid rock with her punches. When her fist clashed with Freed’s while the latter was in his own demonic form, a powerful shockwave was generated, which destroyed the ground below them. She was also able to block a punch from Elfman while he was in Full-Body Take Over with one hand.
Poison Resistance: This form allows Mirajane to have a high resistance against poison, going as far as inhaling the poison gas and calling it a treat.