The Paranoid Saviour of the Previous Civilization

(The author wrote this for fun. It was inspired by a rage after eating a stone in other pre-Civilization fanfiction. And although this book is a pre-Civilization fanfiction, there is no yuri, no yuri, no yuri. The author himself hates yuri!)

A paranoid and arrogant time traveler, guided by a higher-dimensional will (the author), embarks on a journey to save the world in order to return home. He hates the tone of this world and everything in it, and scoffs at the idea that love can save everything. However, in order to return home and save the world, he is willing to give everything he has.

Maybe it's a multi-heroine romance? Probably. I wrote it with a magic tool, so don't expect it to be too logical.