Dekomori Sanae

Biodata

Feature	Information
Name	Dekomori Sanae (凸守早苗)
Alias(es)	Controller of the Thunder Hammer; Thunder Hammer User; Rikka's First Servant
Species/Race	Human
Gender	Female
Affiliation	Far East Magic Society / Organization
Occupation/Role	Student; combat member; examiner for prospective members; website volunteer
First Appearance	Chapter 20

Power Progression

Stage / Realm / Level	Chapter	Notes
Spiritual Power—first stage nearing completion	162	Her Spiritual Power can reinforce her twin-tail weapons and support combat against Evil Spirits; she judges herself close to perfecting the first stage.
Rumble-Rumble Fruit awakening	175 176	Awakens a lightning-based ability, producing blue electrical arcs and attacks such as “One Thousand Volts.”
Elementalization—100% affinity	345	Breaks through while racing the High-Speed Hag, fully elementalizes, and emerges unharmed after defeating it.
Rank Three	346	Reaches Rank Three within the Organization.

Background / History

Sanae first appears as Takanashi Rikka's self-proclaimed “First Servant,” arriving from Shuchiin Junior High to assist Rikka and Hasegawa Izumi. She is already familiar with Izumi's reputation and eagerly wants to see the person who impressed her master. To confirm her place beneath Rikka, she duels her in a consciousness-based battle, then accepts Rikka's authority after losing. 20 21

She holds Mori Summer in exceptionally high regard, considering her second only to Rikka before meeting Izumi. Sanae studies the Dark Grimoire, believes Mori Summer created it, and is assigned to verify whether Nibuya Morika is truly Mori Summer. Though she returns the book respectfully when Morika asks for it, Sanae's idealized image of Mori Summer creates a long-running conflict with Morika. 22 32 67 98 318

Izumi formally recognizes Sanae's qualifications and invites her to join the group after the May Day holiday. She later volunteers to help establish the Far East Magic Society's website, which eventually becomes a channel for supernatural commissions and exorcism-item sales. 32 73 286

Initially confident in her imaginary missions and combat prowess, Sanae acknowledges the large gap between herself and Izumi after the Society begins formal training. She actively seeks more challenges, but Izumi's test reveals that she lacks advanced close-combat ability; he knocks her unconscious with a chop to the neck. 58 106

Sanae develops Spiritual Power through the Society's training, mastering water-walking before the other girls. After awakening the Rumble-Rumble Fruit, she becomes a lightning-based Ability User and begins taking a more active role in real supernatural incidents. 123 175 176

As Yotsuya Miko's examiner, Sanae leads a livestreamed assessment at a haunted bus and tunnel. She pushes Miko to confront Evil Spirits, fights alongside her against a Spider Evil Spirit, and teaches her that raw power must be controlled to make someone a true powerhouse. 160 162 163

Her later work includes defeating the Bewitching Ghost as a trial arranged by Izumi and independently responding to a commission involving Sakurai's possession by an Evil Spirit. Her lightning proves especially effective at exorcism, allowing her to force the spirit out of Sakurai without killing the host. 218 219 286 287

After witnessing a suicide that she could not prevent, Sanae struggles with the responsibility of being strong and the limits of what she can save. She later shows greater maturity by helping a lost child and defending her convictions during an argument with Iino Miko. 243 319

Izumi gives Sanae a trial against the High-Speed Hag. Determined to earn his approval, she surpasses her self-imposed limits, reaches complete elementalization affinity, defeats the yokai, and subsequently attains Rank Three. 344 345 346

Appearance

Sanae is a petite blonde girl with clear sky-blue eyes. She normally wears extremely long twin tails that extend past her knees; sandbag-like weights hang from their tips and can be used as weapons. She initially wears the Shuchiin Junior High uniform. 20

• Her twin tails can swing as “wind-thunder braids” or be reinforced with Spiritual Power in combat. 69 162
• She favors conspicuous outfits, including a pink shirt, floral skirt, striped thigh-high socks, and a small top hat. 49
• During operations, she wears magical-style formal attire and sometimes carries a rabbit backpack. 120 217
• After her breakthrough against the High-Speed Hag, she lets down her long hair and appears noticeably more mature. 345

Personality

Sanae is theatrical, energetic, and deeply committed to her chuunibyou identity. She regularly refers to herself in the third person, ends statements with “death,” and adopts dramatic poses even when confronting genuine danger. 20 217

Her strongest trait is loyalty. She reveres Rikka as her master and Izumi as “Lord Sage,” actively seeking their approval and viewing the Far East Magic Society as a place worth defending. She is also proud of her seniority within the Organization and initially treats newer members with a degree of superiority. 21 185 214 278

Sanae is impulsive, competitive, and easily provoked by Morika or Masuzu. Despite her boasts, she can honestly recognize when she is unqualified, refusing to teach Kato Megumi because she believes incomplete understanding could lead Kato astray. 90 165 287

Her experiences with death, supernatural cases, and responsibility gradually make her more considerate. She learns to restrain reckless behavior during dangerous missions and begins acting on concern for others rather than only on pride or rivalry. 175 243 319

Abilities & Skills

Rumble-Rumble Fruit

Sanae awakens a lightning-based ability that lets her generate, control, and channel Spiritual Power as electricity. 175 176

• Fires electrical attacks such as “One Thousand Volts”; the current can incinerate an ordinary person. 176
• Uses lightning-enhanced movement to cross corridors as a streak of light and rapidly reposition in battle. 218
• Defeats Busujima Saeko through superior speed and attack range. 242
• Lightning has a natural demon-dispelling effect due to its extreme-yang attribute. 287
• Her attacks can be controlled precisely enough to injure an Evil Spirit while protecting its human host. 287
• Initially struggles against Natsukawa Masuzu's Stand because she cannot see it. 176

Elementalization

After her trial against the High-Speed Hag, Sanae achieves 100% affinity with her elementalized body. 345

• Transforms into an elemental state while moving at extreme speed. 345
• Emerges unharmed after pushing her lightning ability beyond its previous limits. 345
• The breakthrough allows her to defeat the High-Speed Hag. 345

Spiritual Power and Spirit Vision

Before awakening, Sanae trains Spiritual Power for physical reinforcement and supernatural perception. 123 160 162

• Masters water-walking before the other Society members. 123
• Activates Spirit Vision to observe ominous energy inside a haunted bus. 160
• Uses her Spiritual Eye to detect concentrated ghostly energy. 217
• Reinforces the sandbag weights on her twin tails, allowing them to destroy ordinary Evil Spirits on contact. 162
• Can clear ghostly restraints by releasing a surge of Spiritual Power through her body. 218

Combat Training

Sanae receives basic close-combat instruction from Izumi but is not a martial-arts prodigy. 106 107

• Uses a Wing Chun opening stance during her fight with Masuzu. 176
• Learns basic combat awareness and improves through sparring. 107
• Initially fails Izumi's physical test and is knocked unconscious before she can react. 106

Equipment / Items

• Twin-tail weights — Sandbag-like weights tied to the ends of her hair; used as meteor-hammer weapons when reinforced with Spiritual Power. 20 162
• Dark Grimoire copy — A replica of Mori Summer's book, used by Sanae for supernatural research and divination knowledge. 67
• Magical formal attire — Her preferred operational costume during supernatural missions. 120 217
• Rabbit backpack — Carried during the Society's outing with Rikka, Masuzu, and Morika. 120
• Laptop — Donated by Sanae for the Society's “Sea of Electrons” activities. 286

Relationships

• Hasegawa Izumi — Her revered “Lord Sage” and mentor. She seeks his approval, receives training and guidance from him, and later realizes she has feelings for him. 21 58 163 345
• Takanashi Rikka — Her master. Sanae serves Rikka loyally after losing their initial assessment duel and remains protective of her. 21 89 296
• Nibuya Morika / Mori Summer — Formerly Sanae's idealized spiritual mentor; their incompatible views of Mori Summer's identity turn them into frequent rivals. 22 98 318
• Natsukawa Masuzu — A competitive rival whom Sanae calls the “Greedy Witch.” They regularly bicker and spar, including a battle after both awaken their abilities. 90 176
• Yotsuya Miko — A junior member whose assessment Sanae oversees. Sanae mentors Miko during the haunted-bus mission and fights beside her against the Spider Evil Spirit. 160 162 163
• Ishigami Yuu — An acquaintance and fellow chuunibyou enthusiast; he calls for Sanae's help during a supernatural emergency. 104 217
• Shirogane Rintarō — Gives Sanae a replacement hairpin after hers breaks; she confesses her feelings for him and resolves to pursue him. 346
• Kato Megumi — A client and potential Ability User whom Sanae brings to Izumi for guidance after declining to teach her beyond Sanae's own expertise. 286 287

Notable Quotes

“The Wicked Eye of the Tyrant King Wielder Takanashi Rikka's First Servant, Controller of the Thunder Hammer, Dekomori Sanae, reporting for duty!” 20

“Wherever Lord Sage resides, that place is a holy land, death.” 163

“Only those who can control their own power are true powerhouses.” 162

Trivia

• Sanae is popular in her class despite sharing Ishigami Yuu's chuunibyou tendencies. 104
• She is prone to motion sickness on trains. 120
• She is wealthy enough to offer Natsukawa Masuzu financial assistance and to donate a laptop to the Society. 173 286
• She initially insists that Nibuya cannot be the real Mori Summer, even after others acknowledge Morika's identity. 98 318