Return of the last survivor

In "Return of the Last Survivor" by Shadow_Magus, Merlin, the last remaining powerful human elementalist, faces the otherworldly zombie monarch, Zero, and the few other survivors of humanity. In a shocking turn, Zero unleashes a devastating attack that obliterates everything. Merlin awakens to find himself alive, returned to a time before the apocalypse, before Zero, and before the zombies. Armed with this foreknowledge, he is driven to protect those he previously failed to save and alter Earth's impending doom. This story features reincarnation, a system with leveling mechanics, an apocalypse scenario, survival elements, modern-day warfare, zombies, and a male protagonist. The narrative follows the last survivor of a planar invasion who is sent back to the system's initiation day, moments before his death. He swiftly establishes a formidable empire before exploring other planes. The author's style becomes unconventional around chapter 100 but later reverts to its previous tone. The protagonist is utterly ruthless with a second chance via the system, a minor mystery unfolds, and there is minimal emphasis on romance or friendships. The story is considered decent with short chapters.