Hell's Handbook - Chapter 439

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.

A striking man of mysterious origin and peerless talent, he looks back at the world, in all its entirety, with utter disdain. And yet, in the treacherous and unpredictable ultimate formation of the Boundless Secular World, he guards a breathtaking ancient qin with broken strings, waiting silently for the destined one to arrive!

Interpol Chu Nanzhi traveled to the last years of the Dahe Empire, and became a wicked woman hated by thousands of miles and eight villages and a vicious mother of four little ones.

But on the first day after transmigrating, she encountered a catastrophe of extermination. She used her past life director to help the original owner’s husband get rid of the crime, and saved herself and the four little ones.

Back home, Lin Jinxiao and the four little ones still hated her and were always wary of her.

Looking at Lin Jinxiao and the four little ones who were sick in bed, Chu Nanzhi didn’t want to give up the truth, and decided to wait until Lin Jinxiao recovered from his injury, reconcile with him, and promised to take care of the little ones temporarily.

Because of being highly valued by the county magistrate and wealthy households, Chu Nanzhi took advantage of this time to become a proficient detective and supported her family by investigating cases. She assisted the county magistrate in solving many cases and gradually changed the attitude of her neighbors towards her.

Later, Chu Nanzhi proposed to make peace with Lin Jinxiao, but the four little ones refused at first.

She went out to handle a case, and the four little ones were afraid that she would never return, so they chased after her: “Mother, we want to go with you,”

When she came to Beijing to meet her, the county magistrate took her hand and refused to let go: “You are already the mother of four children.”

One day, when Lin Jinxiao became the emperor, he put his arms around Chu Nanzhi and said, “You have been trying the case for so many years, so stay in the palace and try it on me, I have grievances!”

- Description from novelbuddy

This is the story of a boy who lived a secluded life in the mountains, tending his farm, rearing his fish, and dreaming his dreams. Eh? Did I suddenly conquer all worlds and become the big boss? Or am I still in a dream?

- Description from Novelupdates