Magnus, a reclusive Old One, polices his Carinthian valley with a pragmatic ruthlessness that belies his human appearance. His introduction sees him in the dead of night, dragging a bundle across a frozen lake to dispose of a lich in a fisherman's hole, a task he delegates to Paul, the gruff Man in the Lake. This casual display of power, coupled with Paul's complaints about the "pollution" and Magnus's inner monologue about smoking cannabis to suppress his urge to "kill someone," immediately signals his dangerous nature. He is a formidable force, preferring human tools like a Glock 17 to magic, which he avoids using publicly to maintain his anonymity. Yet, the city is far from quiet; recent incursions from vampires, a rampaging werebear who broke through an old lady's bedroom wall, and the persistent lich point to a calculated disruption of his territory. When a fae assassin invades his game store, freezing time to demand information about "Old Ones," Magnus's calm facade cracks. He brutally dispatches her with enchanted dice and a flurry of bullets, even breaking a human's finger for cheating with shop window reflections, demonstrating his lethal efficiency and utter disregard for conventional morality when his peace is threatened. This violent encounter reveals the deeper supernatural politics at play, as the fae are clearly targeting his kind, but also reveals a "wanted poster" for two Hammon sisters, Old Ones, hinting at a larger conspiracy that has drawn these dangerous elements into his domain. The question now is: who are these Hammon sisters, and why are so many factions desperate to find them in Magnus's territory?

Following the fae incursion, Magnus learns of a fae tree being cultivated in a local warehouse, a gateway to their pocket dimension. His casual contemplation of using mustard gas on an entire troll tribe—whose chieftain is the city's Minister of Transport—solidifies his reputation as the "demon lord" who "punishes many for the mistakes of one." He storms the warehouse, systematically eliminating the fae and other supernaturals, not with grand spells, but with a blend of grenades, a gatling gun, and enchanted dice, highlighting his preference for mundane, yet effective, tools in combat. Inside, he discovers the wanted poster for Sely and Annia Hammon, female Old Ones, revealing the target of the recent chaos. He confronts a fae child, who is actually an ancient fae in disguise, and uses a poisoned chewing gum to destroy the fae tree, demonstrating his clever ruthlessness against his ancient enemies and preventing further incursions. Shortly after, an ambush by Hammon clan members leads to a brutal melee where Magnus loses control, his vision consumed by a "red haze of bloodlust," as he butchers them. Amidst the carnage, Sely Hammon, one of the wanted sisters, kisses him, triggering a powerful, unforeseen magical bond due to her manipulated marriage curse. This unexpected turn not only traps Sely within his territory but also forces Magnus to confront the possibility of a new, unwanted family, all while having annihilated a significant portion of a powerful Old One clan, ensuring their wrath will soon be directed at him.

Magnus reveals his hidden Bathomeus family mansion, a reality marble beneath the city's lake, and the tragic history of his clan: he is the sole survivor, having avenged his murdered family by killing the traitors. This grim past explains his reclusiveness and violent tendencies, but his new connection to Sely and Annia begins to soften his isolation, culminating in a simple marriage ritual. During the ceremony, Sely's curse—a wild magic enchantment designed to amplify her emotions and desires—reacts to Magnus's love, transforming into a blessing that enhances both their powers. He also discovers her pregnancy, which shifts his priorities towards protecting his nascent family. Simultaneously, the fae's manipulative campaign to discredit supernaturals escalates, leading to widespread chaos in the human world as they openly declare war. Magnus, with the help of his resurrected grandfather Hatlix, a legendary enchanter, creates "The End"—a nano-magic weapon capable of species-wide extermination. At a grand gathering of Old One clan heads in Atlantis, Magnus reveals a video of fae "breeding farms"—women fused to trees as reproductive vessels—galvanizing the Old Ones into a unanimous decision for war. He then personally activates "The End" by crushing the marble, unleashing a wave of destructive magic that effectively commits genocide on the fae, demonstrating his willingness to employ ultimate force to protect his new family and territory, regardless of the global consequences. This act irrevocably alters the supernatural world, forcing a new global order.

With the fae largely annihilated by "The End," the world descends into a new, chaotic order. Human governments grapple with the aftermath, while the Old Ones, now united against a common enemy, begin to openly assert their influence. Magnus, initially reluctant, steps into his role as a public figure, giving interviews where he unapologetically explains Old One society, their "pet" relationship with humans, and his brutal actions against threats like the Gen.Tec. Future facility. His clan expands with the addition of former Hammons, who swear blood oaths to him and Sely, further cementing his power and manpower within his reality marble. Meanwhile, the intricacies of his family life deepen: his grandfather Hatlix, fully recovered and learning modern speech with Cecilia's help, rekindles his ancient romance with Sely's mother, while Annia embraces her role as a tech-savvy Old One, even helping to develop new magical enchantments. Sely's pregnancy progresses, and Magnus grapples with the responsibilities of fatherhood, showing a softer, yet still fiercely protective, side as he trains their adopted "daughter" Kath in magic control. The story concludes with the Bathomeus clan thriving in a world reshaped by their actions, with new generations growing up in a reality where the supernatural is no longer a secret, and Magnus, the "demon lord" turned "hero," faces the ongoing challenges of leading his unconventional family in a world he has fundamentally altered, all while still pondering the mysterious energy network revealed by his ultimate weapon.