Invincible Demigod

Thousands of years ago, there was a war between gods and demons! Thousands of years later, a young man ("Otaku") walked out of the sealed land and obtained "The Origin of Chaos". Did he encounter injustices along the way? Then kill all the evildoers you meet! Spread blood all the way, come on, evil spirits from other worlds! Decisive battle on the battlefield between gods and demons! ···