MTL - Why is the Bright Moon Shining? - Chapter 21

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

Luo Qing Chen is a wandering spirit that died thirty thousand years ago, roaming the Chaos Space

In order to not turn into dust, she is bound by an ice cold system to travel through time and space to complete missions.

Girls that pretend to be weak?  Slap them without explaining.

A silly cannon fodder?  Helping them amass treasures.

Meeting a real male god?  All of them will pamper.

System: Dear masters, what do I do if my host even dares bully the heavens?  Waiting for an answer, it’s urgent!

A certain male god: Change systems.

System: ヽ〔?Д?〕丿

- Description from Novelupdates

In a world where villains are crafted, not born, Vyan's life takes a detour from dull to downright dramatic faster than he can say “abracadabra.”Meet Vyan, the most ordinary knight in the realm, with all the magical prowess of a damp sock. Loyalty? He's got it in spades. Betrayal? Well, that's the surprise twist in his not-so-fairy-tale life.Framed and forsaken, Vyan is left with nothing but a grudge and some pretty gnarly scars, courtesy of his once-master, Iyana. Oh, did he mention she is the daughter of a marquess and the object of his unrequited affection? Talk about adding insult to injury.Just when he is ready to unleash his inner berserker, a butler comes along with news that makes his hair stand on end: Vyan is the last heir of the Grand Duke's mage dynasty!With power crackling at his fingertips and more mana than he can shake a wand at, Vyan is ready to show the world what happens when you underestimate the underdog. Will Vyan rise from the ashes like a phoenix, or will he crash and burn like a fire-breathing chicken? There's only one way to find out.

Xiao Yu, who was a student from modern Earth, accidentally transports to another world and becomes the lord of a territory. Facing an unfavorable situation, he vows to take back his family business, build his new territory, kill all of those who covet his wealth, and dominate the world!

- Description from Novelupdates