The Villainess Enjoys Her Seventh Life as a Free-Spirited Bride (hostage) in a Former Enemy Country - Chapter 2: This time, I want to relax

A mysterious natural phenomenon caused the Earth to be plunged into darkness. The world turned into an endless bloody chaos and mankind is on the brink of extinction…

Chu Yun Sheng, an ordinary white-collar worker, discovered his family heirloom book shining a bizarre light by accident. Out of curiosity, he tried to study the heirloom book.

After a long research, he still only understood a few symbols written in the ancient book. However, he was shocked when he figured out what messages the ancient book tried to tell him: the sun will disappear, and humanity is doomed…

He tried to spread the message, but no one believed him; his family and friends even tried to take him to see the psychiatrist. Eventually, he gave up telling anyone, but prepared for the apocalypse in secret.

Until one day– the sun really disappeared…

- 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.

Su Yun was a prodigy, blessed by the gods. However, life is never so easy. Soon after reaching 6th stage in spirit novice realm cultivation, his progress stagnated due to incurring a rare medical condition.