Childhood Sweethearts: He's Jealous Again! - Chapter 513: Becoming a True Fiancé and Fiancée

An ineffable rebirth, taking advantage of a mystical magic cube that was produced from rebirthing to pass through various worlds(anime, novel, movie, games, etc), collecting whatever I want to obtain!

- Description from MTLNovel

HE WAS SUPPOSED TO AWAKEN A POWER. INSTEAD, HE AWAKENED NOTHING.Louis Lee is the son of two legendary Earth Defenders, but when the superpower evaluation test reveals that he's powerless, his world crumbles. Mocked, abandoned, and broken, Louis becomes a target in a world where strength is everything.But fate has other plans.When a devastating alien invasion shatters the city, Louis is abducted by the same monsters that once killed his parents.Subjected to a brutal experiment, Louis is implanted with a living alien core, a weapon to annihilate humanity at once but instead the core grants him incredible powers making him, half human and half monster.But now, Louis is Earth's only hope of defeating the invaders, but the more he uses the core, the more it mutates him, transforming him into something far more scary.

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.

“For a long time, we humans have been like the chosen race, without any natural enemies, and have long been at the top of the food chain. Unfortunately, I have to tell you...” “When there is only one bird in a forest, then the forest is basically fake, and the bird was put there by someone...” “No matter how a fish swims, it can never meet any of its kind, which only means that the fish is kept in a fish tank...” “Yes, we are the birds in the forest and the fish in the tank.” “Yes, the world we live in is virtual!”