I Said Make My Abilities Average! - Chapter 30

The world is in ruins. Extreme sub-zero temperatures suffocate the surface, making even simple survival an ordeal. Frozen derelicts of bygone eras span across massive ice wastes. And the survivors closely guard any technology rediscovered within.The only escape from the deadly climate is beneath the surface. But it’s another disaster underground. Monstrous machines lurk in the depths. Unhinged demigods war against them, dying over and over, treating it all like a game. The land itself shifts over time, more contraption than rock. And an ominous prophecy states that the key to everything waits on four heroes - but nobody knows who or where they are.When an expedition into the far uncharted north goes terribly wrong, Keith Winterscar and his father get trapped together in a desperate fight for survival. Stumbling upon an ancient war of titanic scale; the two will need to set their differences aside while they struggle against Gods, legends, and the grand secrets of the realm that lies below.

A Hentai World is a Dangerous Place, Especially if Your Best Friend is a Hentai Protagonist and You Are a Trap.

The most famous deed of this princess was her words to her younger brother Liu Ziye.

When he became emperor, she told him, “Although your highness and I are of different sexes, we are the children of the same father. Why can you sleep with so many different women, while I must be only with my husband? This is so unfair!”

And after the Emperor Liu Ziye heard his elder sister’s words, he ridiculously thought it made sense. So he immediately corrected his “wrong ways” and painstakingly selected thirty handsome youths for her to enjoy.

Chu Yu awoke in the princess’s body and realized that she had obtained a male harem of three thousand; should she take just one to drink, or keep all of them?

- Description from Novelupdates

Reborn into the world of Yugioh, it's natural if my goal is to become the best duelist!