MTL - Martial Peak - Chapter 166 Little nephew (first)

When The Cute Kunoichis Spied on Their Teacher's Secret is a light novel written by Kazuma Kamachi and illustrated by Ryuushi Tajima.

The story takes place in a world where Japan never ended their isolationist phase, and agents from foreign powers are always threatening to steal the country's advanced technology. In order to combat this threat there has been a resurgence of ninjas that use Strategic Martial Arts, techniques that combine cutting-edge modern technology with a traditional foundation of martial arts and ninjutsu. The story follows Souha Sugiyado, a 17-year old ninja instructor and former ninja prodigy who was forced to retire from active duty by the wounds he suffered in his last mission. Souha's four students are all kunoichi who have all gained the rank of Elite Ninja, the highest official rank available to ninja. However, one day two Shogunate ninja approach him with the news that his four students have gone rogue and have stolen a portable modular nuclear reactor, and thus they ask for his help in bringing his students to justice.

Shi Jin once read a book. It was supposed to be about satisfying the desire for vengeance.

The main character, also named Shi Jin, was the sixth son of his harem-novel-protagonist-like father. All was well—while his father was alive. But after his death, Shi Jin’s five elder half-brothers tormented him, eventually leading to his death. The protagonist was reborn, determined to take revenge, and… the novel was discontinued.

That day, Shi Jin almost spat blood and dropped the book into a shredder. The next day, he died in a car accident. Somehow, when he came to, he had transmigrated into a teenager, a youth also called Shi Jin.

There was only one problem. His father had just died. His older brothers were about to torment him…

Shi Jin: Let’s eliminate my brothers’ hatred, my goal is to keep my life!

- Description from Novelupdates

Damian, a Centurion of the Punishment Unit of the Baroque Kingdom. “Damn it.” Just once. If I were given just one more chance… ‘I would have truly conquered the battlefield with these guys.’ At the age of 30, he closed his eyes on a nameless battlefield. But when he opened them, he found himself back 17 years in the past. And this time, he had a perfectly functioning mana core that could wield magic. ‘This time.’ I will rise higher than anyone else. I won’t be swept away by the turbulent times. ‘I will conquer.’ Damian, who has returned to the past, wields his spear toward the world.

Zhang Ye was originally a mundane college graduate with aspiring dreams to become a star, but unfortunately has below average looks and height. However one day, he woke up and suddenly found himself in a parallel world!