The supporting character's harem is very normal - Chapter 520: Arine and you?

Death is sometimes not the end!
Dead prison!
This is a magical prison. It has the ability to draw the souls of the dead people of the world, and it also enables people to gain the ability of the souls of the dead.
When Qin Song woke up, he was shocked to find that he had come to the world of One Piece, and even more surprised that he found a prison in his body…..

- Description from Uukanshu

In ancient times, there were seven types of evil thoughts, each of which possessed the power to confuse, and muddle, people’s hearts. Every single person that came into contact with one of the seven, would inevitably undergo a sudden change in personality and temperament, and commit the unforgivable crime of murder.

Determined to rid the world of these seven evil thoughts, Lao Zi forced the seven evil thoughts into seven separate bamboo strips and secured the opening of such bamboo strips with the Phoenix Lock, and, in so doing, finally succeeded in sealing the evil bamboo strips.

But who would have thought, that the evil bamboo strips would, in due course, reappear on the surface of the Earth……

- Description from Novelupdates

Wazu was an ordinary townsman who shut himself off in the “mountain” because of an unfortunate course of events. After 2 years, he decided to come down from the mountain to meet with people. But there were various misunderstanding about the “mountain” which he shut himself off in. And then he repeatedly had encounters with people. And after that. . .

No family, no power, no inheritance — a thrice-lacking protagonist. Just how will the seed rise up from the mud?

- Description from Novelupdates