Nine Heavenly Thunder Manual - Chapter 8 – Return of Ai Er

In the whole world there lays twelve paths to climb the Tower of God, and in legends these twelve pathways leads toward legendary road of immortality. However these paths in the Tower of God, are far too long, without end.

After being given up on by his family because his dantian was destroyed, Soh Woonhwi was kidnapped by the Blood Cult and lived as a third-rate spy.

One day, he died while being used to find a legendary sword immortal’s secret records. However, he returned to the day he was kidnapped ten years ago and obtained a mysterious ability that allowed him to hear the voice of swords.

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

Upon being reborn, she immediately offends a vicious two-faced bigwig.