Chronicles of the Heavenly Demon - Chapter 23: The Five Evils (1)

My Beautiful Teacher tells the story of a university graduate Qin Chao who can’t seem to find a job and is in a downward spiral in his life. Then one night as he walks home from another failed job interview, a vase hits his head, making him get possessed by an old and powerful evil spirit sealed in that vase and following another incidents, inadvertently saved a mysterious university teacher Su Ji, thereby opening his path to cultivation, he also manages to get a job as a security guard at Guangyuan School. A series of adventures then took place as he deals with all kinds of supernatural beings.

- Description from Novelupdates

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.

Qin Yichen returned to his youth with his memories of more than 10,000 years. Superb mental strength, advanced elixir formula, advanced martial arts.

- Description from xbiquge

I finally managed to kill the demon lord.