Shuumatsu no Harem

"In the near future--Tokyo, Japan in 2040-- Reito, a young man suffering from an incurable disease, vows to reunite with his childhood friend Erisa and enters a "cold sleep" to cure his disease. When he wakes up five years later, the world has changed dramatically. The MK (Male Killer) virus has killed 99.9% of Earth's men. With just five men and five billion women, it has become a super harem. Only five men, known as " numbers," are resistant to the MK virus. As one of them, Reito is asked to "mate" with the remaining women for the survival of humankind. A harem lifestyle was waiting for him in a post-pandemic world. Meanwhile, Reito is dragged into the global conspiracy surrounding the numbers. Can he overcome temptation and save the world?" (Source: Crunchyroll, edited)