Esther Rosenthal

Esther Rosenthal (エステル＝ローゼンタール) is a magician who first appears in Toaru Kagaku no Accelerator.

Etymology
was a biblical figure and the main character in the, part of the Jewish and the Christian Old Testament. A Jewish orphan who became the new wife of the Persian king, she asked the king to rescind an order to kill all the Jews in the kingdom (after the vizier was offended by her cousin and guardian  not bowing) and won permission for them to kill their enemies.

is a surname of German and Ashkenazi Jewish origin, meaning "valley of roses".

Appearance
Esther is rather well-endowed and has blonde hair and green eyes. She has a mole under her left eye. She wears a black cloak over a sleeveless white blouse, which is open on the back, with a red skirt under a large belt. She wears two black ribbons on her temples. Her forearms are covered in bandages and she wears gloves. She wears black thigh-high socks, her legs have leather straps, and her ankles are bound with metal rings. She wears dark underwear.

After her clothes got wet shortly after meeting Accelerator, she wore a nurse's uniform during the incident which followed, initially wearing her cape over it before giving it to the Huotou, possessing the corpse of Hitokawa Hasami, to cover up its host's body.

Personality
Esther is shown to be generally kind to people. She is also seen to be completely comfortable when Accelerator walks in on her when she is in her underwear, much to Last Order's chagrin.

She values humans and their lives enough that she is outraged when they are exploited in despicable fashions; this is displayed greatly when, despite how they are dead, Esther does not see any of her animated corpses as expendable as she prefers to see no harm come to them.

Background
Esther is the current head of the Rosenthal Family, who have spent 400 years and 23 generations developing necromantic techniques in order to create the perfect golem, one with a perfect soul and perfect body - a god. She was trained in the family's style of necromancy to pursue this goal (and warned against careless teaching it to others), though she did not fully understand the meaning and weight of life and death. She also inherited the family's tools, including the powerful and dangerous artificial souls known as the Evil Spirits of the Numbers.

At some point within the past five years, Esther came to Academy City and was apparently tricked into joining Hishigata Mikihiko's research team as a supervisor, to aid in their research on where esper abilities originated from in the human body and later strengthening esper powers by reinforcing the physical body. Despite the nature of this research (and the supposed deception), Esther shared her knowledge of necromancy without fully grasping the consequences, enabling them to make considerable progress, though only with corpses, eventually leading to the creation of the Coffins. During this time, she also became friends with Hishigata's younger sister, Hirumi.

However, Hirumi ended up dying under unknown circumstances and seeing her friend dead in front of her, Esther tried to revive her using Taowu, one of the Evil Spirits of the Numbers. While Hirumi's dead body was reanimated, she was not brought back to life. Additionally, unknown to Esther, the Taowu contained the will of her ancestor Isaac and on activation, it was secretly contacted by a self-proclaimed demon who conveyed a method to achieve the goal of the Rosenthal Family by using the memories of 10,000 deaths to bring an artificial soul to Keter. Influenced by Isaac's desire to achieve this goal, the Taowu prioritized and moved to accomplish the plan, disregarding Esther's orders, posing as Hirumi and manipulating her brother to carry out the plan under the guise of making her into a Level 6.

Esther soon realized that she had lost control of the Taowu and that whatever will was guiding it planned to interfere with the processes of life, death and reincarnation, potentially altering the world at a fundamental level. As a result of losing her friend twice, Esther came to understand the weight of life and death, and realizing that they should not toy with death, she abandoned the desire of the Rosenthal Family. Following this change of heart, she ended up being held captive while Hishigata continued to develop the Coffins using the techniques she'd taught him, even using the other Evil Spirits of the Numbers, along with the resources of DA, whom he shared the technology with. She eventually escaped and sought out Last Order, having learned that she would be targeted to obtain the memories necessary for the plan from the Misaka Network.

Necromancer Arc
Esther first appears while being pursued by DA. While escaping them, she enters a certain hospital and finds herself in Accelerator's room. She attempts to ask him about Last Order, however Accelerator doesn't notice her due to using his power to deflect sound away from him while reading. While she tries to get his attention, her pursuer catch up with her and manage to subdue her. She is later tied up with several belts and gagged. Despite her bonds, she manages to get out during the scuffle between the Anti-Skill and Accelerator who has come to take her away for questioning as she carried a photo of Last Order.

She escapes her restraints during Accelerator's battle with Nishio and the prototype Coffin, and later reappears before Accelerator, in his room, inquiring about the girl on the photo, Last Order.

After a rocky start with Accelerator, she tells him of DA and their plans and later bring him to the warehouse where she was restrained. There, they discover a huge mecha, a Coffin known as the Qiong Qi, and find out that DA's plans are already in motion. Later, Esther performs a magic ritual on Hitokawa Hasami's corpse, in order to put her to rest. While doing so, the curious Accelerator touches the physical form of Hasami's residual memory, allowing him to see how she had died. Esther sucessfully possesses Hasami with her Huotou and closes her spiritual circuit but is interrupted by the arrival of DA operatives who have come to dispose of the body. As a result, the Huotou activates and takes control of Hasami's body allowing her to fight for Esther as she is her master.

When Accelerator stumbled after dispatching the first DA member, Esther asked if he was OK and noticed his head bleeding due to his wounds reopening. As the second DA member tried to escape, Esther attempted to pursue him but he used his blade to bring the ceiling down on top of her, though the Huotou protected her using Hasami's body. Seeing her path was blocked, Esther looked for another way, which the Huotou found. After the Huotou told her to hang on, Esther gave it her cloak to cover Hasami's naked body. It then carried her after their quarry, breaking through a wall and intercepting the DA member as he was escaping the hospital.

Toaru Idol no Accelerator-sama
Esther debuts in chapter 6 of the 4koma gag manga alongside Hitokawa Hasami. After Hasami dies after being awestruck by Accelerator's wings, Esther accidentally inserts an artificial soul into her and becomes Hasami's master. From then on, Esther is shown as an unabashed fan of the idol Accelerator being accompanied by her servant Hasami.

Necromancy
She is a Necromancer,  and as a member and the head of the Rosenthal family, can perform Rosenthal family-style necromancy. She can perform rituals on the dead to help them as they're "pass[ing] through the gates of Heaven." An example of this is with Hitokawa Hasami, whom Esther mentions that the corpse would crawl back again even if buried. The ritual involves Esther putting back the wandering "residual memory" of the corpse in order to put her to rest. This requires closing the corpse's "spiritual circuit." Esther places a complex magic circle upon the body of the corpse. Additional magic circles then form upon the floor where the ritual is being made, and a large, vibrant burst of light appears as the spirit is installed. She then "reactivates" her, re-possesses her body with her Huotou, and then closes the spiritual circuit. To do this, she needs the "residual thoughts" as a keyword and then sends the false soul into the body. If the residual thoughts are not controlled, they usually take dangerous form that people sometimes call ghosts.

Slowly, the "residual memory" gathers and forms outside the corpse in the form of a floating brain. If touched, as with the case of Accelerator, the memories of the person can appear in the back of the one who touched its mind, apparently spanning even from birth of the person all the way to their death.

Artificial souls
The Rosenthal Family make use of artificial souls, also referred to as false soul (偽りの魄), which are stored in charms called si-xiong charms and inserted into corpses to animate them. When summoned, the soul is bound to follow the orders of the head of the Rosenthal family. All of the artificial souls that are used by the Rosenthal family have names based on ancient Chinese figures, due to the influence of the Taoism in their spells.

Esther is currently only shown to have summoned and implanted two artificial souls on corpses, Huotou and Taowu. However, as the only living member present in Academy City in the course of the story, it is presumed that she was the one implanted the artificial souls on the corpses that would eventually come to be used by the Coffins, large mecha that would also bare the name of the artificial souls.

Huotou
The Huotou (禍斗), also referred to as the Rosenthal Third Number (薔薇渓谷家参式 (ローゼンタール サードナンバー) ) is used by Esther to possess Hitokawa Hasami after her death, presumably the same artificial soul used when her body was used for the Prototype Coffin. Esther uses the artificial soul in her process in “closing the circuits” of a corpse. When put in a corpse it will take a while before the Huotou activates. When it does, it rises by itself and talks in a strange manner, like that of a robot. When in combat it can be both fast and powerful, and as with the case of Hasami, be able to destroy and create a crater on a floor with a single kick. It also automatically tries to protect its master (Esther), and if in danger of being destroyed, tries to protect the “charm” that allows it to move, allowing damage to the corpse if necessary.

Taowu
Taowu (檮杌), known as Evil Spirit of Numbers (ナンバーズの悪霊) is the evil spirit that possessed Hirumi's body after being resurrected by Esther. Initially, it was thought to be capable of independent and malicious thought unlike Huotou, and unwilling or incapable of speaking. It is later revealed that the spirit has been imprinted with the soul of Esther's ancestor, Isaac, allowing it independent thought and have its own goals.

Armor of the Dead
The Armor of the Dead (死者の鎧) is an armor made from dirt. Esther can envelope her Huoutou with an armor of dirt that not only increases defense but also attack power. To activate this spell, Esther uses one of her magic circles on paper and puts in on the ground where there is a sufficient amount of soil. By Esther's actions however, she apparently needs to continue invoking the spell to provide the dirt for her Huotou's armor. According to her, the spell is just using a Gnome (土精 (グノーム) ) to amplify the defense of the dead and increase its attack power.

Emperor Shun's Blade
Esther has with her a dagger known as Emperor Shun's Blade (舜帝の剣). It appears as a dagger with strange marking that Esther uses as a regular dagger, using it to stab people or to escape being tied.

It can be used for a spell known as Spell of Emperor Shun's Blade (舜帝の剣の術). The dagger is prepared for the spell by using a ritual where the blade is placed in the center of a magic circle. The dagger is intended to neutralize the artificial souls used by the Rosenthal family on striking their charm and is described by Esther as poison to the likes of the Taowu.