Demon's Virtue - Chapter 600: Mental Wall

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.

During the day, she was his secretary, working very hard with excellent abilities. At night, she was his bedmate, trying her best to please him, and the two of them were very harmonious in bed. One day, this relationship was on the verge of ending. However, both of them had already become deeply involved and had grown accustomed to each other's presence, falling in love with each other. So...

She was the godly thief of the 24th century, yet she was reincarnated as a good-for-nothing idiot with no parents. Not only that, she had to bend her will according to her relatives’ mood. Idiot? Trash? Very well, sooner or later, she will show these group of silly earthlings what it means to be too late for regrets!