Save and Reload: Apocalypse Regressor

A tale of ends, the ending of the world, the ending of the mundane, and the ending of peace. Gates around the world appeared, spewing out monsters as soon as they appeared. What was once fiction is now happening, but even people gifted with skills by the system can't fully save the world from devastation. Although one person, a regressor, might just be able to do it... After many... Attempts.