The supporting character's harem is very normal - Chapter 461 Karol Magic Academy.

A chance to change, to challenge destiny, making dreams a reality, and live a legend! A regular man gains a system that allows him to turn into a fish!

- Description from Novelupdates

The ending of fairy tales is usually a happy ending of the hero and heroine. As for the supporting characters, who will care about their happiness? Having such a bad thought one day, they suddenly turn dark. They want to revolt, and they don’t want to be the main couple’s stepping stone for their ‘True love’ again. Oh my god! What’s about the plot? What kind of story will it play out with a character like this? Can it still run smoothly? The hero and the heroine are going to be crippled by the supporting character!!!!! Well, there’s actually a project to save the plot from it. By nipping the bud of all evil thoughts from them, and let the hero and heroine live together in happiness. The named of this project is ‘To save the supporting character’. All executors must dutifully do their work, and as for the mean to achieve it? Oh! That’s not worth mentioning~

No matter whether it is a white cat or black cat, if that cat can catch a mouse then it is a good cat.

- Description from Novelupdates

The mortal body, metamorphosis, longevity, immortality, and eternal life. These five realms, step by step, reveal themselves in front of you. As a normal person, how can one try step by step to reach and open the door to eternal life?

Between the heaven and the earth lies the mortal body, the mysteries of metamorphosis, freedom of longevity, the power of immortality, and the hope of eternal life. A story filled with endless new magic, a new world of immortal styles, people, demons, gods, fairies, magic, kings and emperors. A world of love and hatred, revenge, and mystical battle, all in “Eternal Life.”

- Description from Novelupdates

Xiao Yu’an was reincarnated into a novel. As a cut-sleeve teen emperor. ​Terrible, so sad. Because of this, Xiao Yu’an does his best to continue living. But! It’s fine if you guys want to fantasize about the male lead, but can you stop trying to climb into his bed? Yes he does treat the male lead well, but that’s only because he needs that main character halo!!

Xiao Yu’an: “Stop abusing the male lead!!! You guys aren’t scared but I wanna live!!!”

A story that starts out with Shou taking care of the Gong, then Gong takes care of the Shou.

- Description from Novelupdates