"Riki-Oh 2: Horobi no Ko" is a direct continuation of the original "Riki-Oh" series, expanding on its dystopian and violent narrative. Set in a future where society has collapsed, the story revolves around Riki, a young man with superhuman strength, who continues his quest to dismantle oppressive systems and confront powerful adversaries. The sequel delves deeper into Riki's origins, revealing his connection to a secretive organization known as the "Horobi no Ko" (Children of Destruction), a group of genetically enhanced individuals created to serve as weapons of mass destruction.

The plot intensifies as Riki uncovers the truth about his own creation and the experiments that granted him his immense power. His journey leads him to confront the remnants of the organization responsible for his existence, including its enigmatic leader, who seeks to use Riki and others like him to dominate the fractured world. Along the way, Riki encounters a diverse cast of characters, including former allies turned enemies, fellow genetically enhanced individuals, and survivors struggling to navigate the chaos of the post-apocalyptic landscape.

The series maintains a focus on themes of rebellion, identity, and the consequences of unchecked power. Riki's internal conflict between his desire for peace and his role as a weapon of destruction drives much of the narrative. The story is punctuated by intense, visceral battles that showcase Riki's abilities and the brutal reality of the world he inhabits. As the stakes escalate, Riki must decide whether to embrace his destructive potential or forge a new path that challenges the very system that created him. The series concludes with a climactic confrontation that leaves the fate of Riki and the world uncertain, setting the stage for potential future developments.