Transmigrated as The Forgotten Extra Novel

A comet catastrophe centuries past unleashed a devastating plague upon the southern continent, nearly extinguishing humanity entirely. Survivors retreated behind fortified steel walls—civilization's last bastions against oblivion. Yet within a world crumbling beneath rust and blood, an enigmatic consciousness awakens in an ordinary boy's body. He is Cain, an unremarkable youth thrust into a reality not his own. Beneath perpetual neon skies, Cain fights for survival in a brutal world where merciless fate and inconceivable horrors prowl beyond the iron ramparts. When despair threatens to consume him completely, a system window materializes before his eyes. [Null Sequence requesting installation permission!] A whisper of emptiness offers him salvation—yet demands a price he may never afford to pay.