Harem Investment System: Getting Money And Women - Chapter 212: Silicon City (VII)

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.

The dawn era after the end of the half century has gradually rebuilt the order, abandoned civilization, and is full of undivided violence and desire.
The noble and powerful pioneers are in charge of the city, and the evil and mad plagues are in the wilderness.
Pure human beings who cannot mutate are the weakest, dominated by the rulers of the pioneers, and are not as good as animals in the wilderness.
A purely humanized young man with a worldly experience has quietly entered the WTO, holding a three-foot long knife and a long-distance desire to boil in the world of purgatory. From the nameless name to the sorrow of the Supreme Court, the name of the black ride is resounding!

- Description from Uukanshu (translated)

A generation's mighty and most powerful expert died mysteriously and reincarnated without any memories on a small planet far away from the Cultivation World.

This small planet was earth.

Five thousand years ago, a great calamity descended on earth. Countless Spatial Cracks appeared in the sky and beasts invaded. After hundreds of years of fighting, humans discovered they could awaken a battle spirit that can help them raise their strength and grant them the abilities that were simply unimaginable for humans before.

Qin Feng also awakens his battle spirit but unfortunately, it was swallowed by his own birthmark, The Infinity Symbol.

This was just the beginning of the mysteries that surrounded him like invisible specks of dust. He soon discovered that the 'Infinity Symbol' was actually not his birthmark but something mysterious from another world.

The Infinity Symbol helped him awaken a Divine Battle Spirit and granted him a Nameless Cultivation Technique that was beyond the world's limit.

He also discovered that he could not die! Every time, he was killed, he returned back in time with the memories of what is going to happen in the future.

Soon after awakening the Divine Battle Spirit, a mysterious beautiful lady stepped into his life and told him that he does not belong to the earth. He was actually the reincarnation of someone called 'KING'.

The mysteries that surrounded him like the invisible specks of dust started to come on the surface from the day of his awakening, revealing many secrets to him.

This novel is also known as Don't Mess with the Dark Princess

When trash becomes a genius—one word: Fierce! Two words: Two-faced! Three words: Too heaven defying!

She is the foremost and outstanding armament refining master. Passing through a dynasty, and became a publicly humiliated and bullied Third Young Miss. Ancient beasts, too outrageous? Obediently become a docile pet, or I’ll make you into soup!

Ninth rank talent, rare talent in a thousand years? She was born with a godly constitution, crushing all geniuses!

Peak level Profound Grade Armament, beyond priceless? Sorry to embarrass, but the bowl she uses to feed the cat is already at the God Grade….. she possessed a pair of eyes that could see through everything, yet she couldn’t see through—him!

Merely exposing his demonic smile, Prince Mou lightly loosened his belt: “Can’t see through? Do not fret, you can slowly view when you return to the room. I’ll allow you to scrupulously inspect from head to toe.”

- Description from Novelupdates