MTL - Disassembling System: Begin With Scrapyard Alchemy - Chapter 268 you're done

Holo’s life was once a series of relentless hardships—bullies at school, abusive parents, and heartbreak at the hands of those he trusted. After a failed suicide attempt, a mysterious man offers him a deal: help rehabilitate four psychopathic girls, and in return, earn ten million dollars. Desperate and naive, Holo accepts, not realizing the chaos and danger awaiting him.Each girl comes with her own dark tendencies—Trixie, a violent and feral girl who acts on impulse; Scarlet, a master manipulator who delights in breaking people down; Felicia, a dangerously seductive woman battling a sex addiction; and Eleanor, a cold, calculating girl with a desire to watch the world burn. As Holo works to bring out their humanity, the girls become obsessively devoted to him, their love transforming into something darker.

Ever since she transmigrated, she was blessed with an inbuilt anti-poison detector.

Beep beep – What? Her father’s concubine was evil and her half-sister was vicious?
Beep beep – Ah! She was in an arranged marriage and her husband did not love her?

Who cared? She could kill those evil creatures instantly with her high intelligence.

Her unparalleled beauty attracted countless suitors and her popularity topped the charts. No one was immune, even the emperors and princes were all captivated by her…

- Description from Novelupdates

10 years searching for his lost sibling.

This is a tale that distorts the scenario of an otome game.An orphan girl named Alicia is attacked by a woman trying to steal her body to become the “heroine”. From the fragmentary knowledge she acquires, Alicia learns that this world is the stage of an “otome game” in a “world of sword and magic”.Having learned the truth from the knowledge she obtained, the immature Alicia dismisses the otome game as “nonsense” and runs away from the orphanage to escape the fate of the “heroine”.A villainess aims to take her life. A fake heroine appears. Alicia trains herself using the fragmentary knowledge she has gained in order to survive, growing into the “Strongest Assassin” that is feared by both the Thieves’ Guild and the Assassins’ Guild.