The Crown's Entrapment - Chapter 15

One day, Emperor Wu Ling discovered, every night he would become a stone, kept on the jewellery box of a lady, embarrassing beyond embarrassing.

One day, Zhao Jin Yu discovered, the stone on her jewellery box could actually speak! Awkward beyond awkward.

This stone had a malicious tongue, harsh, two-faced and indifferent, Zhao Jin Yu itched to throw it smashing it to pieces…, who knew one day, wanting to save herself she used it to block a sword, it really did shatter, she cried for a very long time.

Again one day, Zhao Jin Yu was drafted into the palace, she discovered unusually, the emperor was like this he had a malicious tongue, harsh, two-faced and indifferent…

- Description from Novelupdates

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.