I'm at Level 30, But I Can Slay Level-9999 Beasts in One Hit! - Chapter 28: The Human Heart is Unfathomable

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.

An ordinary person who has passed through the Marvel World to gain the phagocyte ability and began to devour superpowers, and became the king of Marvel!

There are many female lords. The protagonist has gradually become the king of the Marvel world from ordinary people. The initial ability is the physique that changes through traversing. It can devour and stabilises without any side effects. The system is only an aid, you can also cross the plane!

- Description from Novelupdates

The Capital’s girls look on with hatred, “ You’re just a country girl without any knowledge. Do you have Cloud Shop’s clothes? Do you have Brilliant Treasure Pavillion’s jewellery? Do you even know how eminent and domineering the famous Yue Wang is?

In a romance novel called “The Secret Lovers of the Academy” the male lead would often torment his fiancée–but wait, why did she cross into this world to become his fiancée, the villainess, instead of the heroine?