MTL - Master of Ninja World - v16 Chapter 26 reason

The ill-fated high school student Liu Yuan obtained the inheritance of the top civilization in the universe and changed his own destiny. He also used many powerful technologies in the inheritance to lead the Chinese nation to rise in the universe.

- Description from novelbuddy

This is a story about a legend, of one that can never be forgotten.
Summer, first time down the mountains in 16 years, after being raised by his 3 masters and Fairy sister.

‘Why won’t you follow the Rules of society?’ The rules are the tool made by the strong, so I follow my own rules.

‘Why won’t you just use your brain instead of your brawn?’ Idiot! Have you ever seen anyone use their brain, to get back at an ant that bites them!? No, they just casually step on it.

‘Oh, everyone says you’re a first-class beauty huh?’ well, I’m sorry but even you are not qualified to be my wife. Only a ‘Summer class beauty’ is worthy enough!

‘My enemy is sick?’ Oh, don’t worry, even if you’re on your last breath and I feel it’s beneath me to slap shot you dead. I’ll just fix you up and then beat you!

‘Who am I?’

“I am Summer in the spring, the autumn, and the winter, I’m the world’s first above the heavens!”

Follow me, Summer Day as I step by step become known as the world’s first master, the world’s first doctor, the world’s richest man…… a lot of other world’s number one, but most importantly, The worlds happiest man.

- Description from Novelupdates

A Consort seeks prosperity.A Shepherd cloaked in yellow wages war.A Prosthesis-wielder cries out for retribution.Shadows tremble in the depths, encompassed worlds obscuring the many dangerous secrets of history. Might they be unraveled, all ways of life would be threatened. But to climb higher requires risks, to seek the light requires a Gambit of Lifetimes.Only when one determines themselves capable of risking it all, can all prosper.

To save a doomed fantasy world, I killed the main characters, then destroyed the game world, and fell into another timeline as the academy's top seat and rival to the protagonist.Now, I'm trying to save the world and steer it towards a better ending…But I'm the final boss.