The Apocalypse Gave Me a Cheat Skill

In a grim post-apocalyptic shelter, an overlooked survivor suffers constant mockery due to his seemingly useless, low-tier ability. His fortunes shift drastically when he realizes his modest gift can purify contaminated food and water poisoned by the surrounding wasteland. After absorbing energy from an enigmatic alien crystal, his dormant power evolves into a devastating heavy cannon. Rather than seeking petty revenge, the newly empowered warrior steps up to defend his community against deadly mutant incursions and internal rivalries. As desperate survivors look to him for salvation, he challenges the shelter's tyrannical hierarchy to carve out a secure sanctuary.