Undertaker

Undertaker is an infinite regressor and anomaly hunter whose repeated lives allow him to turn failed worlds into knowledge for the next attempt. Born Go Yo-il and known to Yu Ji-won as Mr. Matiz, he becomes the central organizer of the Regression Alliance. His greatest strength is not regression alone, but the network of people, institutions, skills, and memories he patiently carries through the world's recurring destruction. (Chapters 1–7, 426, and 460–463)

Biography

Learning how to fail

Undertaker begins each regression in the concourse of Busan Station alongside 398 other people, but death does not give him a clean second chance. The first cycle ends before he can close the station's Gate; later attempts reduce a week-long struggle to minutes, yet each apparent solution exposes a different route to extinction. Even after more than a thousand regressions, he describes his life as a record of failure because survival in one crisis never guarantees that the world, or the people he values, will endure the next. (Chapters 1–4)

His early encounters teach him that repetition carries irreversible costs. Old Man Scho shares the burden of regression but is trapped in his own ritual of love and loss. Undertaker's first awakened skill, Time Seal, can arrest a person outside ordinary time, yet the seal persists even when he regresses. Those confined within it repeat an isolated moment without understanding their imprisonment, and the wider world gradually forgets them. Undertaker's title grows from this power to create translucent, enduring graves rather than from a simple profession. (Chapters 2 and 36–38)

The fifth cycle gives him Complete Memory, converting later lives into an exact accumulation instead of the blurred recollections of his first four runs. He uses that continuity to master languages, swordsmanship, aura, crafts, travel, and the habits of allies and enemies. The same gift prevents grief from fading: every lost companion remains immediate, and his mind eventually represents the world as a landscape of corpses. Hobbies, especially coffee, food, exercise, music, art, and deliberately unhurried travel, become disciplines for preserving the human being beneath the endlessly optimizing regressor. (Chapters 8, 18, 21, 30, 36, 109, and 435)

Building a world from companions

Undertaker gradually abandons the idea that one overpowered fighter can save civilization. He rescues Seo Gyu from the Busan Station death that had prevented him from awakening, then recognizes Website Management as the foundation for SG Net. Jeong Ye-ji's Clairvoyance, Telepathy, and hidden Time Stop become the alliance's eyes and voice, while Noh Do-hwa's workshop and National Road Management Corps reconnect isolated communities. Rather than treating support abilities as secondary, he makes information, roads, medicine, and trust the framework within which combat victories can matter. (Chapters 3–7 and 31–33)

His relationship with Dang Seo-rin gives that framework a political and personal center. He first joins Samcheon World in the fourth cycle and helps her coalition hold Ten Legs long enough for the Great Witch's Cursed Song to reach completion. Across later cycles they build defenses, magical broadcasts, judicial systems, and an enduring friendship organized as much around meals and drink as around war. Their closeness also reveals the danger in his methods: by helping Seo-rin become indispensable to every resident of Busan, he contributes to the route in which her generosity expands into Utopia, a city-sized anomaly that cannot distinguish care from possession. (Chapters 18–20, 54–57, and 109–112)

He applies the same mixture of rescue, training, manipulation, and affection to the rest of the alliance. Sim Ah-ryeon's appetite for hostile attention becomes healing through the Grudge Orb; Cheon Yo-hwa learns to direct her role-imprinting power toward anomalies instead of merely programming people; Yu Ji-won's Mini-map becomes national command infrastructure; Lee Ha-yul's puppets give her a voice and an independent place beyond her father's basement; and Oh Dok-seo turns foreknowledge and fiction into weapons against narrative anomalies. These successes make the alliance capable of protecting humanity, but every corrupted route forces Undertaker to confront how easily his careful cultivation can become another form of control. (Chapters 11–13, 48–62, 69–78, 87–98, 103–112, and 149–159)

Choosing an ending beyond regression

The deepest conflict predates Undertaker's remembered regressions. As Go Yo-il, he meets Go Yuri at his mother's funeral, where the reincarnator claims the place of a sister from another life. She trains him, arranges encounters, and guides him toward the role of the future regressor, while hiding his name behind titles such as Doctor and Mr. Matiz. Yo-il recognizes both her manipulation and her sincere attachment. On the eve of their planned separation, he gives her one of a pair of silver bells and vows that obtaining its counterpart after forgetting her would prove that even her calculations could admit a miracle. (Chapter 426)

That history returns when Go Yuri's innumerable reincarnations converge into a world-ending composite existence. Undertaker refuses both submission to her plan and the simpler victory of discarding her. Inside his divine realm, the Cemetery of the Sea of Corpses and Blood, every dead companion recorded by Complete Memory becomes part of the battlefield. The realm lets his allies express their remembered prime, but it also strengthens Go Yuri because her lives are inseparable from his own memories. Victory therefore depends on the whole alliance: the Saintess controls time, the Cheon sisters invoke Laplace, Ah-ryeon heals impossible bodies, Dok-seo coordinates the narrative front, and Undertaker holds the shared space together. (Chapters 413–436)

After the raid, the alliance appears to surrender its awakened powers through Udumbara inoculation, hoping to remove the final poison from an otherwise saved world. The core members actually receive false injections, leaving the question of ordinary life entangled with continuing responsibility. When Pandora's box later restores bad endings even Undertaker had lost, he must face not only tactical mistakes but the many sincere attachments formed in discarded lives. He does not resolve them by choosing solitude or another reset. Instead, he accepts a crowded, imperfect continuation in which Dang Seo-rin, Jeong Ye-ji, Noh Do-hwa, Yu Ji-won, Ah-ryeon, Ha-yul, Dok-seo, Yo-hwa, Seo Gyu, and even Go Yuri can challenge how he loves and how he lives. (Chapters 437–485)

Appearance and personality

Undertaker is a tall man with a heavily trained physique, a calm bearing, and the controlled movements of someone who has practiced the same physical disciplines for centuries. He is frequently associated with a barista outfit and a cane-sword. Aura reinforcement allows him to move with overwhelming speed and force, but his posture is often deliberately relaxed: sitting over coffee, walking rather than rushing, or handling domestic work with the same precision he brings to combat. Yoo Younghee, seeing him through the confusion of dementia, reads him simply as a polite young teaching assistant. (Chapters 321, 423, and 451–456)

He is patient, curious, playful, and unusually attentive to other people's preferences. He remembers favored meals, drink ratios, speech habits, and tiny signs of discomfort, then uses that knowledge to make others feel understood. This care is sincere, but Complete Memory and regression give it a frightening edge. Undertaker can predict reactions, engineer meetings, cultivate abilities, or inhabit a role for years to produce a desired outcome. He recognizes the manipulation and often feels ashamed of it, yet repeatedly concludes that inaction would abandon people to worse deaths. (Chapters 21, 54–57, 83–86, 149–153, and 448–459)

His defining contradiction is that he values every person while learning to treat entire timelines as provisional. He can kill without hesitation when a route demands it, endure grotesque injuries, and regard his own life as expendable because regression offers another attempt. At the same time, he refuses to reduce love to a single exclusive bond. Food, coffee, shared work, and remembered promises are his defenses against becoming an anomaly who merely calculates salvation. The final restored bad endings expose jealousy and possessiveness he had denied, but they also confirm that his broad affection was never casual: in each life, he gave the person before him his complete sincerity. (Chapters 1–2, 17–20, 351–369, and 474–485)

Abilities and anomalies

Undertaker's powers do not follow a single numbered advancement system. His capabilities accumulate through awakened abilities, centuries of practice, anomaly-derived interactions, and items whose stories survive regression. Their scale does not remove their conditions: regression requires death, Time Seal is effectively irreversible, Complete Memory preserves trauma as faithfully as knowledge, and even his divine realm empowers the enemy whose memories it contains.

Infinite Regression

Upon death, Undertaker returns to the Busan Station starting point while retaining the experience needed to attempt another route. Regression restores most of the world, but it does not place every phenomenon under his control. Time-sealed people and certain bound items persist across cycles, other regressors and reincarnators can create independent variables, and anomalies may recognize or exploit repeated causality. More importantly, regression does not preserve his mental health by itself. He must build routines and relationships that give repeated life a purpose beyond reaching the next failure more efficiently. (Chapters 1–3, 36–38, 86, 117, and 138)

Time Seal

Time Seal is Undertaker's first awakened skill and the origin of his alias. It removes a target from ordinary temporal change, leaving that person trapped in a repeating instant even after Undertaker dies and begins another regression. The seal cannot be undone by regression, and people outside it gradually lose the sealed person from memory. Undertaker used the ability heavily in his first six cycles before understanding its moral cost. He later treats it as a grave of last resort rather than a convenient method of preservation; the story does not establish a universal weakening cost for repeated use. (Chapters 2, 36–38, 77, and 109)

Complete Memory

Acquired in the fifth cycle, Complete Memory preserves experiences with exact detail. It supports language learning, perfect recall of texts and conversations, long-term strategy, and rapid comparison between different routes. It also lets Undertaker reconstruct minute gestures or replay a flashback while acting in combat. The ability is not neutral storage: accumulated deaths remain emotionally and perceptually present, eventually making him see the corpses of companions throughout the world. Udumbara can interfere with that continuity, erasing a run or suppressing access, while Pandora's box can return memories that even Complete Memory no longer holds. (Chapters 8, 18, 30, 36–38, 109, 157, 382, 437–446, and 474–481)

Aura, swordsmanship, and anomaly hunting

Centuries of training make Undertaker one of the peninsula's finest aura users. He reinforces his body and weapons, senses distant presences, creates barriers, crosses great distances, manipulates objects with extreme delicacy, and releases attacks capable of cutting vast spaces. His skill is closely associated with the cane-sword Do-hwa, whose blue blade and accumulated story survive regression. Aura is not inexhaustible or universally safe: certain routes require an “aura diet” to keep Leviathan dormant, Udumbara can suppress access, and fine multitasking still demands concentration. His so-called Sixth Sense is a developed premonition for anomalies and danger rather than a formally explained status-window skill. (Chapters 9, 11, 49, 86, 122, 159, 331, 406, and 446–456)

Narrative and divine-realm authority

Long exposure to anomalies lets Undertaker understand their voices and defeat them through the stories or causal roles they embody. He can exploit an item's accumulated narrative, as when the Walther PPK's identity as God Slayer and Chekhov's Gun guarantees a decisive wound against the Admin of the Infinite Metagame. This authority culminates in the Cemetery of the Sea of Corpses and Blood, a divine realm built from his view of the world and the dead preserved in his memory. Within it, remembered allies can approach their prime if he permits, but Go Yuri is likewise amplified because her reincarnations occupy the same memory structure. The realm is therefore a shared battlefield, not an unconditional personal victory. (Chapters 146–159 and 433–436)

Power progression

Relationships

• Dang Seo-rin: Undertaker first serves as her vice guild leader, then becomes her closest food and drinking companion, repeated beloved, and eventual partner. He helps her build humane institutions but must also confront the Utopia created when her care becomes absolute control. (Chapters 18–20, 54–57, 109–112, 345–369, and 474–484)
• Jeong Ye-ji: The Saintess is his longest-serving strategic partner and fixed support. He trusts her observation and judgment with the whole peninsula; she trusts his plans through years spent alone in stopped time, while concealing affection that eventually demands to be seen outside her role. (Chapters 3–7, 39–43, 382, and 457–459)
• Noh Do-hwa: Do-hwa supplies roads, surgery, prosthetics, and brutally honest counsel. Undertaker funds and assists her work without demanding repayment, and she becomes one of the few people willing to challenge his treatment of himself and his dependents. (Chapters 31–33, 62, 83–86, 179–181, and 443–456)
• Go Yuri: Yuri is sister, mentor, architect of his pre-regression life, and a principal antagonist. Undertaker opposes her manipulation and composite reincarnated form without denying their familial love, making her rescue part of victory rather than an optional mercy. (Chapters 13–14, 39–44, 413–438, and 426)
• Yu Ji-won: As Mr. Matiz, he mentors Ji-won and takes her on the bicycle journey intended to give an abused child room to choose her own life. Her murder of Go Yuri wounds him, but he accepts shared responsibility and becomes the emotional reference through which she learns beauty and trust. (Chapters 423 and 460–463)
• Oh Dok-seo: Dok-seo begins as a reader who mistakes him for a fictional protagonist, then becomes his strategist, ghostwriter, editor, and anomaly-hunting partner. She turns his lives into a narrative weapon and challenges the martyrdom embedded in his preferred endings. (Chapters 23–27, 149–160, 198–203, and 405–441)
• Sim Ah-ryeon, Lee Ha-yul, and Seo Gyu: These early or overlooked survivors become Undertaker's permanent guild and household family. His intervention lets each discover a world-changing support ability, while their privileged familiarity gives them unusual freedom to criticize, inconvenience, and care for him. (Chapters 6–13, 59–74, 113–117, 406–459, and 474–483)
• Cheon Yo-hwa: Undertaker helps Yo-hwa reject the identity imposed by her cult and redirect her role-imprinting power toward protecting her chosen school-family. She calls him senior and eventually joins her alternate sister in wielding Laplace during the final raid. (Chapters 48–52, 87–98, 110–112, and 433–436)

Items

• Do-hwa Cane-Sword: Noh Do-hwa forges the blue-bladed swordstick in the dwarf anomaly village and names it through their complicity. It persists across regressions, becomes Undertaker's signature weapon, and gathers enough history to damage anomalies through both aura and story. (Chapters 86, 89, 122, 138, and 147)
• Silver Bell: Undertaker retrieves a bell from the Busan Station souvenir shop as part of nearly every regression ritual. Its deeper importance comes from Go Yo-il's paired gift to Go Yuri: recovering the remaining bell after memory loss is his promised proof that their bond can survive beyond her plan. (Chapters 3, 36, 86, 101, 117, and 426)
• Walther PPK, God Slayer: Undertaker acquires the pistol from Namsan and layers it with the stories of God Slayer and Chekhov's Gun. It lands the necessary critical wound against the Admin of the Infinite Metagame but malfunctions before the final blow; afterward it is confined beneath National Road Management Corps headquarters. (Chapters 147–158 and 248)
• Infinite Metagame Laptop: The regression-persistent vessel preserves the sealed Admin, its dialogue, and its services across routes, becoming both a dangerous ally and the manuscript ark shared with Dok-seo. (Chapters 117, 158–159, 198–203, and 439–440)
• Noah's Arks: Undertaker leads the twelve-ship operation against the super monsoon, coordinating the fleet with Ji-won's map and Ha-yul's aura-conducting strings. (Chapters 169–178)
• Cheon Yo-hwa's Black Hair Tie: The plain tie becomes an identity anchor within the reconstructed history of the Cheon sisters and the boundary between Yo-hwa and Cheon-hwa. (Chapters 393–404)
• Pandora's Box: Opening the restored time capsule forces Undertaker to confront bad-ending memories and relationships that even Complete Memory had not retained. (Chapters 474–482)