All the women in the apocalypse are mine

The Void Cataclysm, also known as the Void Invasion.
In short, many holes suddenly appeared in the sky, from which emerged a dense mass of evil creatures resembling dark clouds. Wielding blood-red scythes of death, they harvested human lives like wheat, plunging humanity into a great crisis on the verge of extinction.
No one knows how the void came into being or how it appeared on this planet.
Its arrival caught humanity off guard, solving the problem of overpopulation in a single day and taking humanity a giant step toward becoming a rare species.