Versatile: Alternate World - Chapter 188 - The Way Back Home (VI)

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.

The strongest Hero in history, Nakamoto Keisuke.

He was summoned to another world in the spring at the age of fifteen years old, and when he successfully defeated The Demon King, he was already thirty-two years old. He had finished his role in another world and returned to Japan, but the reality that had been waiting for him was, “Middle school graduate with seventeen years of blank period” label. He couldn’t find a decent job and had no choice but to spend his days working part-time.

Before such a Nakamoto, a beautiful girl who self-proclaimed had come to return the favor, appeared. “I’m the reward for Hero who had defeated Demon King”, said Angelica, a girl who came from another world that persistently tempted Nakamoto to make her his wife. Together with a high school girl who looks like Elsa, his beloved girl that he lost in another world, Nakamoto with his cheats skills got caught in a harem life.

When Ye Mo suddenly woke up, he realized that everything around him seemed to have changed: He has been transmigrated into the modern Earth where spiritual energy is scarce. His pretty master from his former world was nowhere to be seen. Most importantly, he found himself in the body of a young man who has been abandoned by his clan for an embarrassing reason…

- Description from Novelupdates

Everyone knew Shen Nianshen so well.
In this world, there would probably be no female creatures that could enter his heart. Even the most beautiful girl in the school was coldly rejected.

Until one day, when there was a basketball match at the school. In the front row of the audience, there was a girl whose head was accidentally hit by the ball.

Shen Nianshen immediately ran to her. Everybody thought that he only went to get the ball. Unexpectedly, he squatted down in front of the girl, stroked her head gently, and asked anxiously, “Does it hurt?”

This a sweet love story between a cold guy and a lively girl.

- Description from Novelupdates