Genius Sword Immortal (Feng Yin Zi Chen) - Chapter 310

There are countless parallel worlds beyond what we know. The people who first discovered this secret named it “Yan Fu”. Each world is a different fruit on a tree, and the person who shuttles through different fruits is called “Yanfu Walker”. Yanfu Walker is given different Heritage and trained to complete Yan Fu missions in exchange for rewards.In modern society, the Martial Arts sects have declined one after another, and martial arts prodigy Li Yan suffers from leukemia, making it difficult to survive by opening an audio and video store. One day, a person named MO appeared and took him into the Yan Fu world under the pretext of being able to cure a terminal illness. So “Hejian Skinny Tiger” Li Yan resolutely stepped into the world of Yan Fu, awakened the inheritance of Gu Huo Bird, and embarked on the path of survival in a different world. The truth of the world, Yan Fu’s goals, the secrets of the walking organization, and the ambitions of the rebel organization are far more than that…

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.

To reward Meng Fan for his bravery before his heroic death, the cosmos rewarded him with a ‘system’, sending him back in time to three months ago, alive.

- Description from Novelupdates

This book is about baby-making.