Counterattack of the Cannon Fodder Chambermaid - Chapter 644

Yohan wakes up ten years in the past, back when he still lived with his uncle and hadn’t yet lost his parents’ massage parlour. With a strange book filled with wellness techniques in his hands, he decides to live differently this time—more aware, more purposeful, and maybe even more fulfilled.

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.

[Shelter System successfully bound to host!][Option One: City of Light, save the survivors in the apocalypse and become a glorious and benevolent savior.][Option Two: City of Darkness, humans who enter the City of Darkness can only become your slaves. And you, will be the devil ruling over the apocalypse.]Sorry, I am no saint, I choose City of Darkness! From today onwards, I will be a villain!

In 2036, mankind landed on the fluorescent Mars for the first time.

In 2052, the first World Budo Tournament will be held, which is also the world’s highest fighting event, and the world is enthusiastic about it.

Xu Jingming, the world’s top player “Gun Demon”, chose to retire when he was twenty-six years old, with an injury left by the competition…

A turbulent new era has begun!

- Description from novelbuddy