Kyoukai Senjou no Horizon - Volume 2B, Chapter 58: Accepted One in the Flower Garden

After transcending to a new world, Ye Xuan miraculously obtained the Swallowing System.

One day, when a novelist woke up from a restless sleep,he realized that he had transformed into his 12-year-old self.

That night, when a Kryptonian spacecraft with a baby fell on Mike Kent’s farm, when he decided to adopt the child, and the golden finger that traveled through was activated, he knew that his life was about to change.

Superman Clark Kent, Professor X Charles Kent, Magneto Eric Kent…

When he became the father of these people, the strongest family was born!

- Description from novelbuddy

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