Abe no Seimei

Abe no Seimei is the strongest onmyōji in Japanese history, a transcendent born between the grimoire Lust and a white-and-golden nine-tailed fox. Long after his bodily death, an individually conscious fragment preserved in his original Art of Onmyōdō Treatise tests Theodore Miller, passes on onmyōdō, and ultimately completes its unfinished struggle against Lust by guiding Theodore through the Eastern apocalypse.

Biography

Eastern Legacies, Quattro, and the Soldun Civil War

Seimei first enters Theodore's life as the individual ego preserved in one of six original treatises into which his power had been divided. When Gluttony consumes the Art of Onmyōdō Treatise, Seimei refuses both the automatic transfer of proficiency and the proposed Synchro. Gluttony explains that his spirit cannot be completely subdued because he had approached the end of mortal existence, while Seimei himself requests a conversation. This is not the historical Seimei returning bodily: the encounter occurs through a soul fragment embedded in the original book, temporarily synchronized with Theodore's consciousness. (Chapters 161–162)

Seimei distrusts the prospect of giving Theodore a system that harmonizes opposing forces, because Theodore already carries Muspelheim's flame and a sea dragon's blood. He therefore imposes the Heaven, Earth, and Human test before recognizing him. The Human chapter reviews lives Theodore has saved and confirms that his strength protects others; the Earth chapter uses the Path of Five Desires to expose alternate lives, temptations, and the self-doubt behind his avoidance of intimacy. Seimei jokes and provokes throughout, but his standard is consistent: power must be joined to responsibility, self-command, and honest knowledge of one's own motives. (Chapters 162–164)

The Heaven chapter places Theodore in unwinnable confrontations, strips away many of his advantages, and makes him experience death hundreds of times until he recognizes that the trial is asking whether he will submit to apparently fixed fate. When Theodore continues resisting, Seimei grants the highest proficiency in the Art of Onmyōdō, integrates the Ring of Muspelheim and Aquilo's Blood Mark into Artificial Yin and Yang, expands Theodore's capacity, and helps him meet the conditions for transcendence. He also asks that Theodore someday grant an unspecified request and warns him never to approach the East's central capital before becoming fully transcendent. Later uses of Artificial Yin and Yang are Theodore's mastery of Seimei's transmitted system, not repeated intervention by Seimei himself. (Chapters 164–165, 171, 173, 175, and 200)

East Continent and the Northern War

On the East Continent, Seimei's warning becomes a practical boundary on Theodore's movements. Gluttony reminds Theodore not to approach the central capital before full transcendence, and Theodore obeys even after his investigation repeatedly brings him near dangerous feng shui and shamanic formations. The inherited knowledge from the treatise lets Theodore recognize manipulated dragon veins, separate spaces, and the lack of a single universal shamanic method. These deductions belong to Theodore using Seimei's recorded knowledge; they do not mean the historical onmyōji is continuously perceiving the world through him. (Chapters 250 and 254–256)

Seimei does act directly when the Receptacle of Solitude's Eight-Tails attacks Theodore with curses. The soul fragment takes temporary control of Theodore's right arm, forms signs rapidly enough to split the incoming curse wave, analyzes the creature's unstable eighth tail and regenerative nature, and helps perform the mantra Breaking Evil and Manifesting Good. Theodore and the mountain spirits supply the destructive force, while Seimei's exorcism separates the accumulated evil from what can still be preserved. The surviving body is reborn as a small three-tailed fox without its former human memories, demonstrating both the precision and the hard limit of Seimei's intervention: the victims had already passed beyond restoration as humans. (Chapters 257–259)

Afterward, Theodore again respects Seimei's restriction and leaves the central capital alone. Within Gluttony's Hall of Fame, Seimei is later identified among the exceptional souls Theodore personally collected, beside figures such as Heathcliff. His accumulated memories include cautions about divination and the mysteries of heaven, reinforcing that inherited expertise carries prohibitions as well as techniques. By the end of this phase, Seimei remains a registered soul and source of knowledge whose larger request is unresolved; Theodore has gained access to parts of his art without yet learning the history that made the central capital personally dangerous to him. (Chapters 260 and 301–302)

Jerem's Return and the Great Forest

During Jerem's return, Seimei's role is mediated specifically through Gluttony's Hall of Fame. Theodore calls the registered soul and spends achievement points to borrow Curse Protection and Protection against the Fallen for ten minutes. The first completely blocks curse magic at or below the 8th circle, while the second increases the damage Theodore can inflict on evil beings. Seimei does not speak, possess a body, or re-enter the battlefield as an independent combatant in this sequence; the Hall of Fame reproduces selected powers attributed to his stored soul. (Chapter 328)

Curse Protection changes Theodore's tactics against the weakened Jerem. Because Nídhöggur's summoning prevents the warlock from using his full 9th-circle power, the borrowed protection covers the curse level he can currently produce. Theodore therefore accepts Grudge of the Afterlife instead of evading it, crosses the distance during Jerem's mistaken assumption that the curse has worked, and closes off his speech with Dragon Words before attacking with Soul Calibre. The protection creates the opening, but Theodore still has to recognize the opportunity and execute the assault. (Chapters 328–329)

Seimei's legacy also helps secure the result after the initial strike. Theodore uses Urgent Order, identified as a spell learned from Seimei, to suppress the separated pieces of Jerem's body so that none can escape and restore the warlock. This victory does not erase the distinction between author and inheritor: Seimei supplies a borrowed anti-curse defense and previously transmitted shamanic knowledge, whereas Theodore combines them with his own speed, soul sword, Dragon Words, and judgment. Seimei's position after the Great Forest is consequently that of a preserved teacher whose specialized safeguards remain decisive even when he takes no personal action. (Chapter 329)

Prometheus and the Eastern Apocalypse

Years later, Theodore's broader study continues to include Seimei's Art of Onmyōdō, and he uses Seimei's shamanism among layered defenses against Sloth. The Eastern catastrophe finally makes the old warning urgent: once Theodore becomes a transcendent and asks directly, the soul fragment discloses that he was born from Lust and a great nine-tailed fox, escaped through his father's intervention, hid in Japan, and built the onmyōji order while protecting the weak. Believing transcendence had freed him from Lust's bloodline authority, the historical Seimei invaded the central capital; his genes still obeyed her, sealing roughly sixty percent of his power, and his brothers died as he was defeated. His former warning is thus revealed as both strategic knowledge and the lesson of his own fatal arrogance. (Chapters 337, 349–350, and 356–358)

Seimei chooses Theodore to finish that failed struggle. He directs him to Japan, identifies the three artifacts he sent home before dying, and teaches him how to connect with the remaining great youkai. He separately contacts Suzuka, the shrine maiden descended from his line, instructing her to give the coming man his legacy and guide him to the sealed youkai. At Tsuchimikado Castle, Seimei opens his old ward and Theodore crosses the shrine's Heaven, Earth, and Human trial because he has already passed it. The three artifacts recognize Theodore, and the Eight Jade Magatamas temporarily gives Seimei's soul fragment a separate visible form; this is an artifact-supported projection, not the historical onmyōji restored to life. (Chapters 358–361)

Able to act beside Theodore but unable to travel far from him, Seimei authenticates the transfer before Suzuka and Japan's masters, helps organize the human and youkai forces into separate armies, and devises a blitzkrieg against the imperial strongholds. At Geongun Castle, his knowledge explains why a crude ward powered by hundreds of millions of sacrifices cannot be broken by technique alone. In the final battle, Suzuka performs a possession ceremony with Seimei's cooperation; using her as a limited vessel, he casts Taboo, Soul Incantation Killing and seals the heavenly demon's Absorption Star Method for one day. The possession permits only one major technique without crushing Suzuka's body and soul, after which Theodore must fight the demon himself. (Chapters 361–364, 368, 370–371, and 374–375)

After Theodore kills the heavenly demon, its remaining information reverses through Theodore's suicide spell and begins eroding his left arm. The returned soul fragment stops him from severing it, invokes the completion of its long-standing quest, and declines a normal Transmission because Theodore's transcendent body is already near capacity. Seimei instead converts his own soul into a spiritual string, uses Yin and Yang Binding to arrest the erosion, and announces that he will take his “little brother” away. The fragment burns up completely after telling Theodore to remember himself when he reaches a crossroads. This is Seimei's final material-world sacrifice: the surviving seal and implanted data are consequences of his act, not evidence that the fragment remains conscious. (Chapters 376–377 and 379)

Marriage, Armageddon, and the New World

During Armageddon, Theodore releases the Yin and Yang Bind that Seimei left on his arm. The seal had preserved part of the heavenly demon's power without leaving its consciousness active, and opening it gives Theodore access to the Absorption Star Method long enough to devour hostile spirits and recharge his circles while confronting Wrath. Seimei does not return for this event; the intervention is a delayed consequence of the soul fragment's extinction and Theodore's use of the dangerous inheritance it stabilized. (Chapter 392)

When Theodore's soul is shattered inside the Akashic Records, an Abe no Seimei appears among the investigators who retain individual personality within the universal record. He is described there as a transcendent born from a grimoire and a great youkai, with a golden tail, and volunteers because Theodore granted his wishes. The corpus presents this investigator as part of Akashic rather than as the book-bound fragment that explicitly burned away. His participation therefore reflects the historical transcendent's recorded ego and gratitude, not a reversal of the fragment's farewell or a bodily resurrection. (Chapter 394)

The distinction is confirmed when Theodore later uses Yin and Yang Binding against Gluttony. He reproduces Seimei's method by turning part of his own soul into a string, but notes that his version is easier because he is alive and transcendent, whereas Seimei had only been a piece of a soul prepared for extinction. Seimei's final position is consequently divided across three clearly different legacies: his historical self is preserved in Akashic, his original-book fragment is gone after its sacrifice, and the knowledge, seals, artifacts, and choices he transmitted continue through Theodore and Japan. (Chapters 394 and 396)

Appearance and personality

The soul fragment appears as a roughly 170-centimeter figure whose sex is initially difficult for Theodore to judge. Seimei has long ebony-black hair beneath an unfamiliar hat, pale skin, bright golden eyes, and white robes woven with red cloth. His eyes appear masculine while his jaw appears feminine, and his beauty combines traits Theodore reads as both male and female, with a silhouette reminiscent of a fox. In the Akashic Records, his historical transcendent ego likewise appears youthful and androgynous but is shown with a golden tail. (Chapters 162 and 394)

Seimei introduces himself ceremonially as the second-generation onmyōji leader of Tsuchimikado Abe, yet he quickly alternates dignity with teasing. He plays a prank with Theodore's hostile dragon mark, needles him about romance during the Earth test, and jokes even when granting life-changing rewards. The humor does not make his tests arbitrary: when the transfer of destructive power is at stake, he becomes severe, withholds knowledge, and judges whether Theodore has used strength for others, maintained his will under temptation, and resisted despair. (Chapters 162–165)

His deepest loyalty is to the protection of ordinary people and to the country he founded. Although born from Lust and a youkai, the historical Seimei rejects his mother's purpose, saves the weak, and establishes a durable order in Japan. He is also candid about his failure once Theodore earns the truth: he calls his defeat the result of inexperience and arrogance rather than blaming fate. That acceptance becomes practical responsibility when he entrusts Theodore with his legacy, plans the Eastern campaign, and spends the last independent fragment of his soul containing the heavenly demon's remnant. (Chapters 357–358, 361–363, and 376)

Magic, abilities, and martial skills

Seimei is a transcendent onmyōji whose art combines shamanic knowledge, ward construction, curses and protections, spiritual techniques, and the harmonization of yin and yang. His surviving fragment is weaker and more restricted than the historical individual: it can communicate through Gluttony, lend recorded abilities, briefly control part of Theodore's body, manifest through an artifact, or possess a compatible vessel, but those modes have different costs and should not be treated as one uninterrupted physical presence. (Chapters 161–165, 257–259, 301, 328, 361, 375–376, and 394)

Mixed origin and transcendence

Seimei is the child of Lust and a white-and-golden nine-tailed fox, making him neither fully human nor ordinary youkai. Lust expected the upper-species child to protect her, but his father removed him from her control, and Seimei later reached transcendence through the shaman's path in Japan. His mature strength is compared to a dragon, and he could reveal nine tails and call a meteor shower. Transcendence removed him from ordinary causality but did not erase the command embedded in his inherited genes; Lust could still paralyze his body and seal most of his strength, the decisive weakness that caused his death. (Chapters 357–358 and 394)

Art of Onmyōdō and Artificial Yin and Yang

The Art of Onmyōdō divides phenomena into yin and yang and harmonizes opposing powers. Seimei wrote six original books, dividing his power among them, and the treatise Theodore consumes contains enough of his soul to retain an independent ego. After Theodore passes all three trials, Seimei grants maximum proficiency and directly balances two antagonistic imprints into Artificial Yin and Yang. The resulting circulation strengthens both powers and makes them more responsive to Theodore, supporting later combinations of fire and water; those later spells demonstrate Theodore's development of Seimei's system rather than Seimei casting through him. (Chapters 161–165, 171, and 173)

Wards, divination, and exorcism

Seimei's wards remain active centuries after his death. Tsuchimikado Castle's defenses can block spatial movement, attack an unauthorized traveler, admit Theodore through an emergency order, and protect the shrine with the same Heaven, Earth, and Human criteria used in the original-book test. His Causality Mirror reviews the lives affected by Theodore's past actions, while his memories warn that divining the future work of the heavens is taboo. Against Eight-Tails, his signs disperse a broad mixture of curses and his Breaking Evil and Manifesting Good mantra removes accumulated evil, though it cannot restore victims whose humanity and memories were already lost. (Chapters 163, 257–260, 302, and 359–361)

Protections and spiritual sealing

The Hall of Fame records Curse Protection as a ten-minute defense that completely blocks curses at or below the 8th circle, and Protection against the Fallen as a ten-minute increase to damage against evil beings. Seimei's stronger spiritual art, Taboo, Soul Incantation Killing, forms a blade that strikes the soul rather than the flesh and seals even an immortal-grade predatory power, but using it through Suzuka allows only one technique before the vessel risks destruction. Yin and Yang Binding is still more costly in his final state: the fragment turns itself into a spiritual string to restrain the heavenly demon's remnant, consuming its own existence in the process. (Chapters 328–329, 375–377, and 396)

Teaching, possession, and command

Seimei transfers more than isolated spells. He tests prospective inheritors, expands Theodore's capacity, imparts extensive shamanic knowledge, and teaches a method for linking to the souls of great youkai. His direct-control modes remain conditional: during the Eight-Tails battle he controls only Theodore's right arm; the Eight Jade Magatamas gives his fragment a separate projection that cannot move far from Theodore; and Suzuka's kinship plus cooperation permits a single high-output possession technique. Beyond combat, he reads an Eastern strategic map, identifies dangerous bloodline concentrations, and organizes the human and youkai armies so their incompatibility becomes a two-front advantage. (Chapters 162–165, 257–259, 358, and 361–375)

Power progression

Relationships

• Theodore Miller: Seimei begins as a wary examiner who refuses Theodore automatic access to his art. Theodore's conduct wins his recognition, and the relationship develops into teasing mentorship, strategic partnership, and mutual trust. Theodore completes Seimei's failed war against Lust; Seimei then destroys his own fragment to save Theodore's arm, and the Akashic investigator later helps restore Theodore because his wishes were granted. (Chapters 161–165, 250–260, 301–302, 357–376, and 394–396)
• Lust: Lust is Seimei's mother and intended to use him as a powerful protector. He rejects her purpose, escapes, and later attacks her central capital, only to discover that her authority remains encoded in his blood. That failure, including the deaths of his brothers, becomes the unfinished responsibility he entrusts to Theodore. The heavenly demon born from Lust is the “little brother” whose remnant Seimei finally binds at the cost of his soul fragment. (Chapters 357–358 and 375–376)
• Gluttony: Gluttony preserves and mediates access to Seimei's original-book fragment, first attempting a Synchro and later registering him in the Hall of Fame. Its systems provide conversation, borrowed abilities, quest completion, and Transmission, but Seimei retains enough autonomy to refuse transfer, set tests, and choose an alternative final reward. The fragment returns to Gluttony after leaving Suzuka, then extinguishes itself through the binding. (Chapters 161–165, 301, 328–329, and 375–376)
• Suzuka: Suzuka is Seimei's distant descendant and the thirteenth shrine maiden associated with his office. He contacts her through his tablet, authorizes the transfer of the three artifacts, manifests before her to prove Theodore's claim, and later uses her willing possession as the vessel for Soul Incantation Killing. His restraint is explicit: he limits the possession to one technique so her body and soul will not be crushed. (Chapters 359–361 and 375)
• Jerem: Seimei never confronts Jerem bodily in the Great Forest. Instead, Theodore borrows Seimei's anti-curse protection and uses a learned Urgent Order to exploit the weakened warlock's reliance on curses. Their conflict is therefore a clash between Jerem's necromancy and Seimei's recorded safeguards, executed by Theodore through Gluttony's Hall of Fame. (Chapters 328–329)

Items

• Heavenly Sword: One of the three sacred artifacts Seimei sent back to Japan before his death. It can turn even distant clouds into a blade and later accepts Theodore, who channels sword power and great magic through it. The blade is damaged in Theodore's battle with the heavenly demon and retained afterward for a future use rather than returned to the shrine. (Chapters 358, 359, 361, 363, 376–377, and 379)
• Eight Mirrors: Seimei describes the mirrors as capable of returning even divine power. Theodore uses them to wash away and reflect the heavenly demon's curses, creating an opening for allied suppression techniques. Unlike the other two artifacts, the mirrors remain intact and are returned to Suzuka for safekeeping in Seimei's shrine. (Chapters 358–359, 361, 374, and 379)
• Eight Jade Magatamas: The magatamas create separate bodies. They first allow Seimei's soul fragment to appear independently from Theodore and later generate Theodore's combat clones. The artifact bears much of the reaction from Theodore's final attack against the heavenly demon and shatters completely, so it cannot be returned with the Eight Mirrors. (Chapters 358–361, 363, 375–377, and 379)