The Guide is Actually a Body-Switching Esper [BL] - Chapter 2: It is what it is

Time travelling from the majestic era after the Recuperation of Reiki, he became Kimura Kazuki, a 16-year-old high school student in Japan, one year before the Reiki Recuperation.

Tentatively, he set out to hone himself to the bone, burning candles at both ends to stockpile resources in preparation for the imminent Recuperation of Reiki. His goal was to be many steps ahead of all humanity when the time comes.

However, it seemed like fate had decided to play a cruel trick on him.

One year later, the Recuperation of Reiki… did not happen as expected.

- Description from Novelupdates

Cho Ryu Hyang was good at math from a young age. When he enrolled into the The Theoretical Maths and Martial Arts School, the teacher, Jo Gi Chun, recognized Cho Ryu Hyang’s talent immediately and took him in.

A scientist, Duan Yixin, transmigrated into another world. She possessed the body of a sixteen-year-old girl but had not inherited any of her memories. With a broken marriage engagement and no money in her hand, she only wants to earn money peacefully. It's a pity that fate always plays tricks on people.When she thought she could finally live peacefully, she discovered that this world was not as simple as she thought. The man she rescued was the notorious ruthless general, and the woman who stole her ex-fiancé was the female protagonist of this world.She looked up at the sky and asked, “God, are you kidding me?”A few years later, on their wedding night, she stared at him and said seriously, “General, I'm not your white moonlight.”The man lowered his head and whispered in her ear, “Mhm, you are not my white moonlight, you are my life.”

Kazekaze thought he was just an ordinary kid in the world of Naruto.- No Sharingan.- No Byakugan.- No Ōtsutsuki bloodline.Just a normal seven-year-old trying to survive in a ninja-filled world.That was… until his father brought him back to Konoha.And he discovered the terrifying truth:* Senju Hashirama, the God of Shinobi, is his grandfather!* Senju Tobirama, the Creator of Ninjutsu, is his great-uncle!With the blood of legends flowing through his veins, Kazekaze must rise to become a shinobi worthy of his lineage.A Genius Among Monsters—But Can He Surpass Them?