The Overlord of Blood and Iron (WN) - Chapter 34

Rokuhara Souta picked up a phone with a mysterious “Friendship System” installed. On that phone, he met an online friend with the nickname “Tokisaki Kurumi.”This online friend was a total roleplay enthusiast—her portrayal of Kurumi was so convincing it was almost eerie.Finding it amusing, Souta humored this hardcore chūnibyō (delusional teenager) and casually chatted with her.Since it was all fake anyway, he spoke without restraint, often throwing out flirtatious remarks just for fun.Until one day, he received an invitation from Tokisaki Kurumi to meet in person.And then… he transmigrated!In a filthy, bloodstained alley, dismembered human limbs lay strewn in the corners, the pungent stench of blood stinging his nose.Standing before Souta was Tokisaki Kurumi, fresh from a kill, smiling sweetly as she gazed at him…(Tentatively planned heroines include Kurumi, Oshino Shinobu, Military Princess(Re:Creator), Kamado Nezuko, Ereshkigal, Leticia… and more.)

“Wang Cheng, we need to practice more!”

“No, I want to guarantee eight hours of sleep every day.”

…

“Wang Cheng, it’s almost nine o’clock, and you’re late.”

“Didn’t you go to work at nine o’clock? It’s still a minute away. Where’s the punch card machine?”

…

“Wang Cheng, what variety show do you want to be on?”

“Is there a fishing variety show?”

- Description from novelbuddy

The formless ancient world was infested with despicable demons. They hunted and feasted on mankind, keeping the human civilization constantly in a weak and suppressed state.

A man who was once called the world strongest agent ended up becoming a teacher after his retirement to train the new generation of agents. After many years of training his disciples, he is killed at the age of 60 by the ploy of a secret organization and was reincarnated in another world with all his past memories.Though he was surprised by the magic and the strange species of that world, he adapted very fast to his condition as a newborn and took advantage of it. He acquired special magic and gained a massive amount of strength thanks to his tight discipline in order to reach his goal: resume his career as a teacher which he left halfway through in his previous life.This is the story of a man who based on the memories and the experiences of his previous life, became a teacher who travels through the world with his new students.