Maou-sama no Machizukuri! ~Saikyou no Danjon wa Kindai Toshi~ - Volume 1 Chapter 22

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.

I, Lin Yun, with my exceptional aptitude, had thought that I would be trained as a key disciple, however...“The Demon Sect will never expect us to send such an excellent disciple undercover. Once you attain a high position within the Demon Sect, with our help both from within and without, why would we worry about the Demon Sect's destruction?”Three years later.“The Righteous Path will never expect us to send such a promising disciple undercover. Once you attain a high position within the Righteous Path, with our help both from within and without, why would we worry about the Righteous Path's destruction?”Lin Yun: I just want to quietly cultivate to immortality...

Space, System, Treasure, Spirit Tools … other protagonists all have golden fingers, Shi Qing: this young grandpa [Xiao Ye] is a golden finger.

It’s just that …he is now a golden finger and even more importantly bound to a host?

And so this host, has a backstory resulting a bloody darkened heart and soul, truly a psychopath!

A psychopath I can endure, but I also have to work together with the psychopath through different worlds, can I endure?

Ancient times, modern times, apocalypse, futuristic….

Traveling throughout the worlds, Shi Qing thinks the host isn’t as bad as he imagined? Strange.

- Description from Novelupdates

It was just like any other day, or so I thought at least. The birds were chirping up on trees, clouds were rolling by the bright blue sky and Elves were dumpster diving in the alleyway.

Okay, one of those three didn’t sound right...

I had a boring life once. Recently though, it has become less boring... to put it one way.

Finding a random Elf in the dumpster? Heh, must be a Monday.

A normal person would have walked by. A normal person would have ignored it.

I must be a pretty weird guy, then.

Now I have this Elf swearing her allegiance to me. What’s next, vampires?