The Undying Wanderer in the Monster Apocalypse

Sixty-seven years after the monster apocalypse, humanity has retreated into shelters. Awakened ones hold power over force, food, and the right to survive, while ordinary people are registered as conscripts, and any hint of resistance gets them thrown outside the city as bait. Zhou Jin's awakened ability is called 'Self-Healing.' In everyone's eyes, this is the most useless low-tier ability: it can't defeat monsters, only let him hold on a few breaths longer than others. Until he is torn apart in the wilderness, and his scattered body reassembles in the dark of night. He discovers that not only can he not die, but he can also control his body to split, stretch, and reform. Others grow stronger by competing for rare monster cores. Zhou Jin grows stronger simply by coming back alive, again and again. The shelter wants to make him an unkillable tool, but the monsters in the wilderness call him 'the one who never decays.' Zhou Jin follows no one. He only wants to cross the monster-infested wasteland to find the last message left by the old civilization— The world is not dead; it is just waiting for a body that cannot be killed. — Description from novelcodex.org