Ichiban Ushiro no Daimaou - Volume 7, Chapter 4 — A Fairly Large Battle

In previous life, I was just a mediocre guy, and accomplished nothing.

After reincarnation, I seize the opportunity of being a legend of the times. In this life, I am the protagonist in Tianxuan World, a great master of martial arts and a founder of making elixirs. What? You want to compete with me in weapon and equipment refining? Then, you should know the Craft God is my disciple…

- Description from Novelupdates

In a world dotted with World Entrances to a demon world, demons have invaded humans for centuries. Humanity has united and one of the most ancient sects in the world, the Archean Mountain Sect, has set up an entire education system in the form of Dao Academies and defenses at the World Entrances.

In the City of Crime, one law stands above them all: Only the strongest can live.

A man is reborn into the world of Avatar: The Last Air Bender as a waterbender from Katara's tribe. Best of all, he was the same age as her, and he had a system with him to help.He knows the future and a system that lets him continuously get stronger by completing quests or long-term missions, as well as giving him the ability to copy abilities from others for himself. He will become invincible in the world of Avatar, even more so than the Avatar himself.