The Wrong Way to Use Healing Magic - Chapter 5Vol 18.

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.

What if a wisp, with zero EQ about human culture and habits, gains the opportunity to cultivate and finally achieve human form? Now he can enter cities, experience technology, and fight his way to the top, right? In this universe where wisps are seen as nothing more than cultivation resources, a wisp stands up to challenge the wisps destiny! Not without causing a lot of misunderstandings on his way, of course…

Zhong Yansheng lived for eighteen years. After accidentally falling into the water, he dreamed and found that he was living in a book. In the book, he was a fake young master who was mistakenly adopted by the Marquis. After the real young master came back, he {real} was not taken seriously by the family and was driven to a separate courtyard in the suburbs of Beijing. His parents only doted on him {fake}, and they turned the real young master into a black hearted man, and finally his family was ruined. After waking up, Zhong Yansheng learned the news that Master Zhen returned to the house three days ago, but the whole family only revolved around him {fake} who was sick.

Third Miss Luo relies on her father’s power to create chaos everywhere and is notorious for bullying the weak. When she had nothing to do, she led a group of servants to the streets to flirt with beautiful and handsome boys. For Princess Qingyang, if this kind of person dared to behave wildly in front of her, she would just kill her with a single finger—until she opened her eyes again and found that she became Third Miss Luo, Luo Sheng.

- Description from Novelupdates