The descent into the Netherworld reaches a devastating
psychological precipice as the relentless journey of Riko, Reg, and Nanachi brings them to the inescapable depths of the fifth layer, Ido Front. Driven by an unyielding desire to uncover the truth about her mother, Lyza, and the profound mysteries of the Abyss, Riko pushes forward despite the mounting physical and emotional toll. However, their path is abruptly blocked by the enigmatic and terrifying Sovereign of Dawn, Bondrewd. This charismatic yet utterly sociopathic scientist operates a secretive research facility, utilizing orphans and children as tragic test subjects in his relentless quest to understand and harness the lethal curse of the Abyss.Bondrewd’s welcoming facade quickly shatters, revealing a calculating monster who immediately views Reg’s unique robotic nature and Nanachi’s tragic history as invaluable assets for his horrific experiments. The group is manipulated and ensnared, leading to a harrowing confrontation that tests the absolute limits of their endurance and loyalty. Nanachi, haunted by the traumatic memories of their past
transformation and the cruel cruelty inflicted by Bondrewd upon their beloved companion Mitty, is forced to confront their ultimate abuser once again. The psychological trauma threatens to completely break Nanachi, yet the fierce bond formed with Riko and Reg provides a fragile spark of resilience.Desperate to rescue their friends and escape the nightmarish laboratory, Reg unleashes his devastating incinerator power, inadvertently draining his energy and leaving them critically vulnerable. The narrative pivots into a brutal, high-stakes battle of attrition where raw physical strength is not enough; survival requires sacrifice, cunning, and profound emotional fortitude. In a heartbreaking climax, Prushka, Bondrewd’s fiercely loyal and loving adoptive daughter who befriended Riko, falls victim to her father’s supreme ruthlessness, being coldly converted into a Cartridge to weaponize the curse of the Abyss for his personal evolution.Fuelled by righteous fury and agonizing grief, Nanachi and Reg launch a desperate, all-out assault against the seemingly immortal Bondrewd, who continually shifts his consciousness into new bodies. The fierce struggle forces Reg to push his mechanical body past its absolute safety thresholds, unleashing a catastrophic display of destructive power. Through sheer tenacity, strategic ingenuity, and the ultimate sacrifice of Prushka’s essence—which manifests as a powerful White Whistle—the children finally breach Bondrewd’s defenses. Mortally wounded yet fundamentally transformed, the triumphant trio leaves behind the blood-soaked horrors of Ido Front. Carrying the heavy legacy of their fallen friends and armed with the newly forged White Whistle, Riko, Reg, and Nanachi step forward into the sixth layer, the Capital of the Unreturned, bracing themselves for the irreversible, terrifying finality of their downward pilgrimage.