Hitting Up The Big Leagues with a Tea Personality - Chapter 224

A man who was once called the world’s strongest agent ended up becoming a teacher after his retirement, to train a new generation of agents. After many years of training his disciples, he was killed at the age of 60 by a secret organization’s ruse and was reincarnated in another world with his memories intact. Though he was surprised by the existence of magic and the strange species in that world, he quickly adapted 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 rigorous 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 students.

Riding out the apocalypse on a tropical island isn't exactly a vacation. When mana arrives on Earth, Coop finds himself isolated in paradise with only one real option to survive. He needs to claim a civilization shard and level up. Coop maximizes his chances by carefully selecting a class and committing to progression. He’ll need to grind thousands of monsters to compete on the system's leaderboards while upgrading his settlement to represent the factionless.

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.

Step into a world where science meets the unknown, where mechas clash in brutal duels, and where every Biocore holds a mystery waiting to be unraveled.Follow Nioh, a genius weapons designer, as he uncovers lost technology, battles biomechanical titans, and pushes the limits of power, in an intergalactic thrilling adventure