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

Xu Xiuwen, who was battered and bruised, was reborn and found himself back at the farewell dinner after the college entrance examination. It was the year 2005. Facing the aggressive former love rival and the childhood sweetheart he once had a crush on, he decided to start a new life. After being reborn, he not only wants to recover the white moonlight that he missed in his previous life, but also builds his own business empire. Fame and fortune, career and love, he wants them all!

This is a story about a badass,

Ryu Han-bin, the main character who fell into a new world after being chosen as a ‘suitable person’.

Because of the error in the guidelines, the training is repeated endlessly…

She, a 21st century mercenary queen, had crossed over into a tragically betrayed body of a waste. Waste? She will show them what it means to be a waste! Betrayed? With the Ancient Manual in her hands, she will astonish all the despicable men and cheap women!

Wait! Didn’t everyone say that she was an evil woman which everyone feared? Why is his Third Highness, full of mystery and charisma, so interested in her?

- Description from Novelupdates