The supporting character's harem is very normal - Chapter 53 Lathel vs Alec (1)

An advertising director is reborn in 1988 Hollywood as an eighteen-year-old blond-haired westerner named Eric Williams.

Xuanyuan was reborn into a strange new world where training to be a Xian was a cornerstone. There was however something ancient dwelling inside his body. He could now devour all of creation…

This is the journey of an ordinary boy and his transformation into the supreme being that reigns over all existence! Everywhere he went, he could not help but tie his fate with numerous women. It did not matter whether they were a goddess or a devil…

- Description from Novelupdates

In the post-apocalyptic age, men were damned.

Arthur finds himself reincarnated as a spider in a dungeon after discovering his magical skills in a world of magic and mystery. He knows that everything in this world can evolve into something greater. Arthur begins his journey to evolve himself into a human by conquering one of the most powerful and mysterious dungeons.As he starts his journey, he finds new allies and enemies who look different from him—some who become like brothers and others who may betray him.Finding himself at the center of world politics, Arthur somehow creates his own monstrous kingdom from scratch, determined to live the life he wants and protect the people he loves. In his kingdom, he needs not only power but also strategy, as gods, demons, and other races use their own tactics and powers beyond imagination to maintain control and conquer worlds. Arthur embarks on his journey to live the life he desires... but will he succeed?