Evolving into a Great Dragon From a Koi Fish - Chapter 380 - River of Spirit Power

More than ten years later, this sentence gradually spread in Elbaf Continent:

Never use magic to deal with tyrants, because you will find that he will return your spells to you thousands of times after being strengthened by countless magic specialties.

This is the story of a dragon-shaped self-propelled fort that keeps doing things in another world.

There is nothing that one magic can’t fix. If there is, then there are more. ——Izawa

- Description from novelbuddy

In his first life, he was the legendary hero who achieved the impossible, slaying the Demon King. But his reward wasn't glory, it was betrayal. Feared by the gods who ruled the world, they conspired to strike him down, murdering him without mercy.But Kai's soul managed to reincarnate in a modern and ordinary Japan. However, after a tragic accident on Earth, Kai returns to the world where he was once killed.Lyla, the tenth goddess and the only one who didn't betray him, never stopped watching him, she has waited for this moment for centuries. Her love is as vast as the universe... and just as dangerous. To protect her favorite, she has sacrificed her power to grant him a tool never seen before, The System.Now, Kai with no memory of his first life and Lyla must navigate a world fractured into nineteen kingdoms, dominated by the religions of the other nine corrupt gods who feast on the faith of the masses. With an obsessive goddess by his side and a power that grows constantly, Kai begins his grand revenge.

From the outside, Nana’s life seemed simple. She had everything she had ever wanted: a cute but rascally pair of twin brothers, a best friend, and her own restaurant. Nana couldn’t ask for anything more; she was happy and content in her life.

A legendary powerhouse of his generation, tired of the bustle of the peak, returned to the ordinary city and started a new life as an ordinary teacher. He wrote the legend in the city.

Magnificent mountains and rivers, the rising powerful ones. Some ancient martial art masters stood at the peak, becoming legendary. Some financial crocodiles rose up in the minuscule places, laughing arrogantly.

However, watching the school beauties was better than fighting and killing; educating was better than fighting for fame.

- Description from Novelupdates