Transmigrated as The Forgotten Extra Novel

Centuries ago, a massive comet collided with the southern continent, releasing a catastrophic virus that nearly destroyed civilization. The remaining humans survived by taking shelter within the steel fortress walls of their last strongholds. In this decaying world of metal and blood, a mysterious boy named Cain awakens from an inexplicable slumber. An ordinary person thrust into an unfamiliar reality, Cain finds himself trapped beneath an endless neon sky, struggling to endure in a harsh new world filled with cruelty, despair, and terrifying dangers lurking beyond the iron walls. As despair threatens to overwhelm him completely, a system window materializes before his eyes, offering an unexpected lifeline. The Null Sequence requests permission to install, whispering a promise of salvation—but like all salvation, it comes with a cost that Cain must be willing to pay.