The supporting character's harem is very normal - Chapter 287 Lathel vs. Alec, Harris

Feng Lingxi was the traditional family’s head mistress – a person with a charismatic yet sly personality with the ability to attract people easily to her side, and having the potential to take someone’s soul away. Crossing across boundaries from a decade ago to now, a world that gives woman full respect and acknowledgement….

Don’t be fooled by her, because she was someone who would act obediently in front of a crowd but, stabs them in the back when necessary! Disguising as someone that would gain her trust and belief! That was why the Emperor of Xian started doting on her, allowing her to become absurdly daring to do whatever she liked. This made the Empress speechless to tears.
That would be the cause of the kingdom’s downfall in the near future…

- Description from Novelupdates

Hell Ghost Wang Wannian is born again, smiling and proud!
What?
Are you a soldier, will the tank drift?
You are a master, can you give birth to dragons and tigers?
You are a superman, can you call the wind thunder?
Excuse me, I am not targeting anyone, everyone in my eyes, it is rubbish!

- Description from Uukanshu (translated)

In the face of absolute strength, every scheme proves futile. Yet, acquiring such strength demands substantial resources.Resources? Wealth?'Money is the last thing I care about,' – Tyler White.“Fellow Daoist, what are your superpowers again?”“I am rich.” (☞ ͡° ͜ʖ ͡°)☞

After dying, you wake up and realize you've been reincarnated as a background character who is judged as human trash.The decision to change your destiny comes instantly.Discovering that your identity isn't as simple as you thought, you feel favored by the heavens when you manage to become a powerful character.Katase: You won't fool me. I'll expose you for the pervert you are.Murayama: ...Thank you for saving us.Issei: Motohama, what happened to you? How are you so powerful?Rias: If you join my peerage, I wouldn't mind being yours.Sona: You beat me in the game. That means you're now my fiancé.Yasaka: Honey, Kuno wants a little brother.Kaori Houjou: Shinji-kun, let's go on an adventure.Kaede Kazama: Shinji-kun, thank you for saving me from that ball.Rie Sawada: Shinji-kun, I'll wait for you. You'll be my future husband, fufufufu...Changing known history and taking it in a direction not even his eyes could perceive, he didn't stop no matter what. Not even the other world was safe from his clutches.Lexia Von Arselia: My hero, and my future husband...Shinji advances without stopping.“I, Shinji Motohama, swear here and now that I will reach the top of both worlds.”