Yandere Step-Mom - Chapter 40: Tease

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.

Omnipotent A-Grade Cool Female Lead VS Secret Passionate and Domineering Male Lead That Loves Assuming and is Easily Jealous

This novel is also known as The Yun Family's Ninth Child is an Imp!

She was an unprecedented assassin, a trump card deadly agent, but transmigrated through into Ye City’s number one prodigious good-for-nothing young miss.

I am an ugly woman? I will break out from my cocoon into a gorgeous butterfly that will blind your snobbish eyes!

I am useless piece of heap? Lightning in my hands, I will smite you to a well-cooked crisp!

Her greed and lust for money had no end. She is lewd to the core with no bottom in sight, sworn to have love fortunes blossom all around her. However, a certain someone holding a blade in the left hand and a sword in the right hand began cutting those love fortunes one by one!

The person smiled with perked brows, “Little Ninth, it looks like I have to let you become occupied!”

- Description from Novelupdates