Mitou Shoukan://Blood-Sign - Volume 1, Afterword

The protagonist of the collapse of the three former civilizations is Dr. Mei. What is the end of logic, the strongest brain, super intelligence, this is the story of the strongest scientist of Honkai with knowledge of the moon becoming the god of science!

- Description from novelbuddy

The worst and strongest villain.I became the narrow-eyed character Arsene Adel.“Revenge.”It sounded good.At least to the original owner of the body.But from my point of view, the goal is not revenge, but survival.I didn’t have the confidence to survive among humans, soㅡI went to the Demon Realm.Where I was headed,A school for demons that is said to be attended by the children of prestigious families in the demon world,……It was a school that terrorized the human world.

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.

Starting from today, I am retired. But what should I be doing? I neither have the skills, nor the mind to do business, my only advantage is this pair of hands which have taken this world. What a headache…

Note: The usage of the term “retired” here doesn’t mean retiring from old age, work etc. It’s a specific term to refer to not involving oneself in the affairs of a certain society.