Parasyte: The Grey

Nadia keeps dying and reliving her 36th birthday party. She's trapped in a surreal time loop -- and staring down the barrel of her own mortality.

Shy Natsu awakens as part of a group chosen to ensure the survival of humanity. Together, they have to survive on a changed Earth.

One day in the middle of the pacific ocean a miracle occurred, a new continent appeared out of nowhere! The new continent was the home for new and mysterious plants, creatures and minerals! Humanity is excited as the age of exploration has returned.

Fuutarou Uesugi is a poor, antisocial ace student who one day meets the rich transfer student Itsuki Nakano. They argue but when Uesugi realizes he is to be her tutor, he tries to get on better terms. While trying to do so he meets four other girls.

In an alternate history where the male population is nearly decimated, eligible men serve as concubines to the woman shogun inside the walls of the Ooku.