Isekai Maou to Shoukan Shoujo Dorei Majutsu - Volume 8 Chapter 1 part4

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.

Even though he lived in America, Tang Cu had been deemed the “godly author” since his debut 8 years ago on a famous Chinese online novel website. However, many people did not know he had a severe social anxiety disorder which caused him to be considered “cold.” After being invited to do an interview for the company’s 10 year anniversary celebration in China, he finally gathered his courage to meet with his #1 fan, Pian Yu.

Pian Yu had been following Tang Cu’s novels for his entire career and, after noticing the lack of romance in Tang Cu’s popular novels, they wrote fanfiction for his novels to include the ‘romance’ Tang Cu left out.

However, Pian Yu turned out to be a male college student named Lu LianGuang.

- Description from Novelupdates

Throughout this current life of mine, I will pay no attention to my past lives, nor will I seek future lives. I wish to live vigorously, to pay back debt of gratitude and fulfill duty to avenge, to defeat valiant heroes from all species, and to proudly laugh at all the Gods and Demons of the Six Path of Reincarnation!

Shennugou is an old and infertile place. It’s hard to find a woman to marry here.