MTL - The Existence of Harry Potter - Chapter 8 slip

When an S-class elite assassin-raised captain of a special ops suicide squad comes home from a high-stakes Africa mission, he finds himself offered something that could potentially set him up for life- a curious assignment that he could use to finally exit his days of war and slaughter.

Then placed into a high-school setting, Lin Yi is tasked by the chairman of a top-tier multi-billion company with bodyguard duty for non-other than his own daughter, a certain little Miss of said high-school.

His enemies, once ranging from drug lords, mafia bosses, political figures, and national leaders, are soon replaced with spoiled kids who happen to have rich papas and mamas, and Lin Yi finds his intense expertise and high-threat skillset misused, and very underwhelmed…

But he does get a harem cast as diverse as his old enemies, so Lin Yi decides that, for the sake of messing around with girls as an invincible entity in a down-leveled environment, leaving his bloody and death-filled war days behind is something he’d definitely want to strive for.

- Description from Novelupdates

She is a two-faced and fierce hidden ghost doctor,

An ordinary man, Ye Chen traveled to the cultivation world by accident and became a phenomenal immortal of that era. After 3,000 years in the cultivation world, he was betrayed and traveled back to earth through a spatial tear.Five years had passed in the mortal world, but when he came back with his abilities, he found out he now has a daughter!