Worlds Beyond Ruin

Seven years after the fall of Mirekun City, survivor Leon Mercer lives in a world consumed by REV X-99, a mutated rabies-based virus that transformed humanity into horrifying predators known as Shades and Nightmares. Trained as a Runner and carrying the scars of countless losses, Leon fights an endless battle beneath the Barrier Ring, believing that survival is all he has left. Everything changes when a mysterious portal tears him from his ruined world and throws him into a peaceful one. There, he meets Shiori Aizawa, a gentle girl whose kindness challenges everything Leon believes about himself. Alongside her friends—Haruto Minase, Daichi Kurogane, and Airi Tachibana—Shiori offers him something he thought he had lost forever: friendship, trust, and a place to belong. But Leon carries a terrible secret. REV X-99 still lives within him. As portals continue connecting both worlds, the bonds between them grow stronger. Yet the deeper Shiori and her friends become involved in Leon's life, the closer they move toward the nightmare he desperately wants to keep them away from. When they are suddenly transported into Mirekun City itself, they discover the horrifying truth behind the world that created Leon—a city where one mistake means death, Nightmares hunt with terrifying intelligence, and hope is often the first casualty. As ancient mysteries surrounding the portals begin to surface and the shadows of the Arcadia Research Bureau (ARB) stretch across worlds, Leon and his friends must confront impossible choices. To save each other, they will have to face monsters, infection, and the darkness within themselves. Because sometimes the greatest battle is not surviving the apocalypse. It's learning that you don't have to survive it alone.