The Monsters' Undertaker

One day, a meteor falls on a once peaceful Earth, and 'Immortals' begin to appear all over the world. These individuals experience a phenomenon where, immediately upon dying, their entire bodies 'reset' to a specific point in time. Society is thrown into chaos by this super-scientific phenomenon, where even wounds or scribbles acquired after the reset point completely disappear. Now, 200 years later. Scientists have yet to unravel the secret of eternal life, and the Immortals are hunted by the state, living as fugitives or lab rats. For these beings who live on, unable to die, a rumor begins to spread from somewhere. A rumor of a man who can grant death to Immortals, a man known as the 'Undertaker'...