Argus spends his first six years treating his human life as a temporary inconvenience, clinically observing his parents and manipulating his environment with tiny bursts of mana. He creates his first minion, a house spider named Thesis, viewing her purely as a defensive asset to protect his core room. The turning point arrives when his drunken, resentful father, Frank, throws Thesis into the garbage simply because she spooks him. Argus attempts to summon his old dungeon authority to kill Frank, but his physical body betrays him, leaving him weeping on the floor in absolute helplessness. He realizes that his vast knowledge of trap-making and monster breeding is utterly useless against the sheer, irrational cruelty of a human adult. The absolute lack of control he experiences as Jason, compared to the total omniscience he wielded as Argus, breaks his clinical detachment. Charlie, his perceptive kindergarten friend, guides him through the grieving process by sharing the story of her dead dog, Wolfgang, and teaching him to bury an empty box in the yard to externalize his pain. When Argus whispers his first genuine declaration of love to a dead spider in the rain, the narrative shifts from a quirky reincarnation comedy to a grounded emotional drama. This emotional awakening fundamentally alters his mana manipulation, as he discovers that intense human emotion acts as a catalyst for involuntary magical bursts, allowing him to finally stretch the physical dimensions of his bedroom. He vows never to let his defenses be breached twice, a promise that directly drives his obsessive fortification of his home and school.

Driven by the need to secure his territory and protect his new spider, Theory, Argus pushes his mana manipulation too far and contracts a severe human fever. In a desperate, agonizing bid to escape his failing biological shell, he condenses his mana into a physical dungeon core, accidentally fracturing his consciousness into two distinct entities. The human mind experiences raw, overwhelming emotion and physical pain, while the core mind operates with cold, hyper-calculating logic, effortlessly managing complex spatial geometry. This dual perspective allows him to remotely dungeonify his elementary school, converting its foundation into a massive mana-generating hive teeming with mutated insects, giant salamanders, and a massive snake named Noodle. However, this massive spike in magical output attracts Alex Richter, a dangerous mage from another dimension posing as a school counselor. Richter detects the mana anomaly and attempts to siphon it using technological harvesters brought in through the school's loading dock. Argus responds by pumping mana into Noodle, turning the snake into a glowing, armored leviathan that smashes through the hallways and slaughters Richter's mercenaries. This establishes a terrifying new dynamic where a six-year-old child commands a subterranean monster army to defend his playground, directly escalating the conflict from local family drama to a supernatural turf war and forcing Argus to realize that his enemies will not play by the rules of a traditional dungeon delve.

The turf war culminates in the school parking lot when Argus, overconfident in his newly reinforced biological body and his supersonic spider, Theory, confronts Richter directly. Richter shoots him, and when Argus attempts to mind-control him, Richter fakes submission and impales Argus's chest with a concentrated mana spike, piercing his physical heart. As Argus dies, time freezes, and his consciousness expands into the cosmic void, where he communicates with the enigmatic Watchers beyond the veil. They reveal that his existence is tied to the very fabric of reality, challenging him to end his story proudly rather than as a victim. This cosmic validation reignites his will to live. Argus forcefully knits his chest wound back together, abandons his arrogant human dueling tactics, and fully embraces his true nature. He drops Richter into a spontaneously generated subterranean maze, bombarding the mage with mutated fire-resistant beetles and pitfall traps. When Richter tries to blast his way out, Charlie arrives and casts a custom dizzy spell, disorienting the mage long enough for Thesis and Theory to bind him in steel-strong webs and drop him into a spike pit. This victory proves that Argus cannot rely on human bravery or physical confrontation; he must fight like a dungeon, using the environment and his swarm to overwhelm his enemies.

With Richter defeated and his power secured, Argus decides to reveal his true nature to his Mother, terrified that she will reject the monster living in her son's skin. He transforms her bedroom, turning foam floors into hardwood and summoning his giant spiders, before floating his physical dungeon core in the air, bracing for her screams. Instead, the narrative delivers a brilliant emotional reversal: his Mother is entirely unfazed by the magic, focusing solely on whether he is truly her son. When he confirms he remembers being born and loves her, she breaks down in tears and embraces him, cementing their bond and proving that her love transcends his monstrous origins. However, this heartwarming climax is immediately undercut by a chilling revelation. His Mother informs him that Frank has abandoned them, having run off with a strangely dressed babysitter. Argus instantly recognizes this babysitter as an agent of Richter's organization, realizing that his enemy's remnants have kidnapped his abusive father. This shifts the narrative momentum from a defensive war to an offensive rescue mission. Argus realizes that as long as his family exists outside his direct control, they will be targeted. This propels him toward his ultimate, terrifying goal of turning the entire planet into his dungeon to ensure his Mother's absolute safety, setting the stage for a global conquest.