Level 4 Human in a Ruined World - Chapter 399

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.

Freshman student Yang Dingtian possesses the Nine Yang Body, found only 1 in million. His Yang Fire is incomparably vigorous and thus, he cannot be near a female’s charms for his entire life. On the night of his 19th birthday, he decided to bid farewell to his virgin life. After stealing and tasting the forbidden fruit, he spontaneously combusted as the result!

In death he crossed over to another world; a world that held respect for Martial Power. His, originally, catastrophic Nine Yang Body was the Nine Yang Body that couldn’t be seen in a millennium! He was saved by a mysterious old man when he was at his last moments and the old man received him for a disciple, then betrothed his daughter to him. Thus, in this odd way, Yang Dingtian became the successor of the largest clan under Heaven, and became the number-one-beauty-under-heaven’s fiance.

- Description from Novelupdates

The poor Commandery Princess is down and out. Her father died when she was young, and her mother passed away not long ago. Her grandfather, the only one she can rely on, is now at death’s door from his illness. Faced with the merciless uncle, the greedy aunts, as well as cousins competing to present the model of the worst relatives, the Commandery Princess could do nothing but feel depressed in heart.

A Pill Emperor of his generation was set up by a traitor.

Since then, the world lost a Qingyun Zi and gained an invincible silkpants.

Once again, walking the Great Dao of Alchemy.

How can I defy the heavens . . . with the medicine in my hands!

- Description from Novelupdates