The supporting character's harem is very normal - Chapter 454 Lathel returns.

“F**K! I'm dead!”That was the first word I muttered after regaining my memories from Earth.Reincarnating into a world of cultivation should’ve been a blessing. Adventure, immortality, power—what’s not to love?But then I remembered what my family did.My sister just broke off an engagement with a crippled young master—definitely a future protagonist.My mother ripped a Dao Bone from my cousin and gave it to me—guaranteed future revenge arc.And me? I’m already a third-rate villain: bullying weaklings and flaunting my Bai Clan name.Worst part? Despite the Dao Bone, I’m still trash at cultivation.My only hope?The System... which I’ve had for years.“I just never realized... It was in English!”

Here, only those with spiritual roots can cultivate while those with mortal roots are destined to stay mortal.

Mo Wuji only has mortal roots, but will he only remain as a mortal?

- Description from Novelupdates

[Hi, I am Poppy Hardy, Your system general manager. You have finally gain access to the entire fund on the system. Congratulations. $100,000,000,000,000 have been unlocked. You can now donate as you want. You can now investment as you want. You can spend as you want. Good luck host. Become the most beloved man on earth] Once bullied, once humiliated, once he begged like a dog, but now everybody wants lick his feet. Ethan Winston, The remarkable Giver! Godly Investor! To hell with you all. I would provide and protect those in my heart!

Son of a bitch! I just finished this godawful fantasy novel, and now I'm knee-deep in it – as David, the disgraced son of the Solarian Empire's top general! Talk about some twisted cosmic joke. But hold on a damn minute... maybe this isn't all bad. Armed with the knowledge of that trashy plot, I can become the ultimate shadow player, an overlord perhaps. Screw the damsel-in-distress harem too – it's time to pull the strings and become the real power behind the throne. This isekai might be a steaming pile, but I'm rewriting the ending with a little more... Debauchery (wink wink).