Tatakau Shisho - Volume 2, Chapter 6: Final Past — Slaughter – Part 2

This is a story of an ordinary boy gaining unusual powers from his nightmares… It all started when Lin Sheng experienced something strange on what he thought was just another normal day. He begins to have recurring dreams that lead him on an incredible journey of discovery as he encounters spine-chilling monsters and elusive secrets.

Third Miss Luo relies on her father’s power to create chaos everywhere and is notorious for bullying the weak. When she had nothing to do, she led a group of servants to the streets to flirt with beautiful and handsome boys. For Princess Qingyang, if this kind of person dared to behave wildly in front of her, she would just kill her with a single finger—until she opened her eyes again and found that she became Third Miss Luo, Luo Sheng.

- Description from Novelupdates

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…

At the end of the story, I found myself in the body of a hidden villain, betraying the heroines. Since I’m not particularly concerned about the end of the world, I’m calmly waiting for the finale… “You’re the only one who truly appreciated my painting of the boa.” “When I make plans to meet you at four, my heart starts racing at three... is this what they call being tamed?” For some reason, the heroines are starting to take an interest in me.