Tatsuya Shiba

Biodata

Background

Tatsuya belongs to the Yotsuba Family and serves as the guardian of Miyuki, the family’s next head. Both the Yotsuba Family and the military provide powerful backing, although the two have competing interests concerning him 16 65.

Retsu Kudou identifies him as Miya’s son and states that the military took him from the Yotsuba Clan three years earlier. Kudou had previously taught both Miya and Maya 136.

At First High School, Tatsuya is placed in Course 2 because of his poor practical examination results. Miyuki maintains that the examinations do not suit his abilities, while his actual combat performance repeatedly contradicts the assumptions attached to the “Weed” label 19 22 23.

Appearance

• Build: Somewhat thin and frail-looking, despite possessing tremendous explosive physical power 2.
• Hair: Described as tousled during his visit to Yakumo Kokonoe 48.
• School uniform: Lacks the flower emblem associated with Course 1 students 12.
• Usual demeanor: Commonly maintains a calm or expressionless face, though praise for Miyuki draws a rare smile 3 57.

Personality

Tatsuya’s priorities center on Miyuki’s safety. He declines an invitation to homeroom so he can wait for her, avoids unnecessary attention because of his guardian duties, and treats possible exposure of their secrets as a security concern 3 22 65.

He is reserved rather than indifferent to friendship. Chiba Yeyou’s intervention during an uncomfortable cafeteria encounter leaves him quietly appreciative of being cared for. He later expresses sincere gratitude for Yeyou’s help with Miyuki 8 30 114.

Tatsuya is pragmatic about responsibility and conflict. He refuses to promise leniency for Sayaka Mibu when that decision belongs to the school, and he recognizes how public praise of his engineering can unfairly undermine other technicians 51 113. When discussing Chiba Yeyou’s strength, he also refuses to offer a definitive comparison without supporting data 88.

Abilities & Skills

Decomposition

Decomposition is one of Tatsuya’s innate specialties. It can dismantle equipment, including weapons and data-storage devices 51 54 73.

• Destroys the storage device targeted by terrorists in the library’s special reading room 51.
• Reduces armed criminals’ guns to scattered components while supporting Mikihiko Yoshida 73.
• Is distinct from Chiba Yeyou’s Quantum Shatter; Tatsuya recognizes that the two spells operate through different mechanisms despite superficially similar effects 91.

Regrowth

Regrowth is identified alongside Decomposition as an innate ability. Tatsuya can repair himself, although Chiba Yeyou notes that traces would remain after such self-repair 37 54.

Elemental Sight and Sequence Analysis

Tatsuya can read an Activation Sequence as it unfolds and analyze the resulting Magic Sequence by sight 12 74.

• Uses Elemental Sight to locate fighting during the school intrusion 51 52.
• Tracks Masaki Ichijo’s forming attacks closely enough to target their magic circles individually 126.
• Cannot analyze Chiba Yeyou’s magic in the usual way because Yeyou’s magical bands contain no visible magical characters 86 87.

Cast Jamming and Countermagic

Tatsuya uses countermagic to disrupt opponents’ spell activation. His explanation describes using two CADs to generate interfering and opposing effects, then replicating and amplifying psion signal waves as non-systematic magic 33.

• Interrupts enemy casting while advancing toward a monolith 120.
• Dismantles Masaki Ichijo’s attacks one by one under sustained pressure 126.
• Has a relatively short range and requires simultaneous magical operation, limitations acknowledged by Tatsuya and Yeyou 33.
• Benefits from Yeyou’s CAD optimization, but remains constrained by competition hardware 124 126.

Material Burst and Mass Explosion

The text identifies Mass Explosion as Tatsuya’s strategic-class magic and separately describes Material Burst as decomposing matter to the molecular level 78 107.

• Uses Material Burst to destroy the burning car that Yeyou launches above the competition bus 67.
• Uses Material Burst lethally against an armed No Head Dragon member 135.
• Cannot freely demonstrate military-secret magic in public competition 78.
• Cannot compress Mass Explosion to the degree of Yeyou’s tightly controlled attacks 107.

Flash Cast and CAD Operation

• Flash Cast: Serves as Tatsuya’s benchmark for exceptionally fast spell activation; Miyuki’s accelerated casting nearly approaches it during Icicle Destruction 112.
• Dual-CAD operation: Can operate two CADs simultaneously, but this does not give him Yeyou’s ability to cast different spells through a single CAD 72.
• Mumble Flash: Uses the spell during Monolith Code; Yeyou’s calibration substantially improves its activation speed, though it does not completely incapacitate the opponent 120.

Magic Engineering

Under the concealed identity of Taurus Silver, Tatsuya is associated with implementing the Loop Cast System and advancing specialized CAD software. He privately acknowledges that Yeyou had achieved comparable work earlier without publishing it 24 57.

Martial Arts and Fieldcraft

Tatsuya combines rapid movement, close-quarters skill, and anticipation rather than relying solely on spell output 23 121.

• Reaches Hattori’s back before Hattori finishes operating his CAD 23.
• Easily subdues two library intruders with martial arts 52.
• Repositions to prevent Masaki from interfering with Yeyou, then defeats Masaki with an intense sound attack delivered beside his ear 126 127.
• Resists a dizziness-inducing substance well enough to feign unconsciousness, alert others, and expose an attempted data theft 148.

Limitations

• Restricted accessible psions: His low mobilizable output puts him at a disadvantage against Masaki under competition conditions 124 126.
• Equipment dependence: An optimized competition CAD still cannot match the capabilities of his specialized equipment 124.
• Uneven practical casting: Some spells he develops take too long for him to activate usefully 100.
• External suppression: Yeyou’s Quantum Vacuum briefly prevents him from using magic while also erasing the attacks around him 126.

Equipment

• Silver Horn CADs — Specialized pistol-shaped CADs associated with Taurus Silver and optimized for the Loop Cast System 24.
• Custom holster — Carries his two Silver Horn CADs; he wears it at school to become accustomed to drawing them 57.
• Competition CADs — Lower-performance devices calibrated by Yeyou for Monolith Code 120 124.
• Magatama Relic — Brings the Relic to FLT in his briefcase while hostile actors target it 148.

Relationships

• Miyuki Shiba — Younger sister and the person he protects as guardian. Her safety takes precedence over his curiosity and desire for an ordinary school life 3 4 65 148.
• Chiba Yeyou — Friend, technical peer, and Monolith Code teammate. Tatsuya values his support but remains wary of his information-reading ability; he eventually accepts that friendship need not require uncovering every secret 65 114 120 130.
• Yakumo Kokonoe — Martial arts master and information source. Tatsuya consults him about Hajime Tsukasa and Yeyou’s background 48.
• Harunobu Kazama — Military superior who briefs him on threats, restricts public use of classified magic, and asks him to cultivate friendly relations with Yeyou 60 78 79.
• Kyoko Fujibayashi — Military colleague and his first hacking teacher. She warns Haruka Ono against investigating her “important partner” 79 154.
• Mayumi Saegusa and Mari Watanabe — School leaders who recognize his analytical and technical abilities and support his participation beyond Course 2 expectations 19 56 97.
• Erika Chiba — Classmate and trusted combat ally; Tatsuya relies on her to intercept Sayaka Mibu during the library incident 2 52.
• Leonhart — Friend and Monolith Code teammate for whom Tatsuya prepares specialized equipment and practice 120.
• Mikihiko Yoshida — Friend whom he supports in combat and challenges to adopt a less self-defeating view of his abilities 73 74.
• Shizuku Kitayama and Honoka Mitsui — Competition participants supported by his equipment and tactics 97 105.
• Masaki Ichijo — Monolith Code opponent whose sustained attacks expose Tatsuya’s competition-equipment limitations 124 126 127.

Story Role / Major Arcs

Enrollment and Public Morals Committee

Tatsuya meets Yeyou amid open mockery of Course 2 students and joins him at the new-student assembly. Yeyou later recommends both Tatsuya and Erika for disciplinary duties 2 14. When Hattori dismisses Miyuki’s assessment of her brother, Tatsuya accepts a practical match and defeats him almost immediately 22 23.

School Intrusion

During the unrest surrounding Sayaka Mibu and Blanche, Tatsuya investigates suspicious recruitment, responds to the library attack, and prevents the theft of classified material. He confronts Mibu over the thieves exploiting her opposition to discrimination 47 48 51 52.

Nine Schools Competition

Initially proposed as a technician despite concerns about his Course 2 status, Tatsuya earns recognition through CAD calibration and original tactics 56 59 113. He subsequently joins Yeyou and Leonhart in Monolith Code, defeats Masaki after Yeyou intervenes against a dangerous barrage, and takes part in retaliation against No Head Dragon 120 126 127 135 136.

His victory over Ichijo prompts the Ten Master Clans to seek a subsequent demonstration of their own strength, turning his performance into a political issue 138.

Relic Investigation and Armed Crisis

Tatsuya brings the targeted magatama Relic to FLT during a cyberattack and later exposes an attempted theft at the Robotics Research Club 148. During an armed takeover, he coordinates with Yeyou to engage separate groups of attackers. Jumonji subsequently witnesses him saluting Kazama and realizes that he belongs to the military 156 159.

Notable Quotes

“A world of equality where everyone is treated the same does not exist. An equal world that ignores talent and aptitude is a world equally indifferent to everyone.” 51

“The reality is that the criminals were successfully subdued because of your magic. That’s the only fact.” 73