A once peaceful world was brought close to extinction and oblivion after a strange event that caused the demon realm to be combined with the mortal realm of the humans. The demons that invaded the world spread about havoc and destruction. The humans, who tried to fight back with their technology, had been defeated. As time passed, the demons becoming the ruling race, humans became docile and mainly went into hiding, with few towns still having human rights or safety. Technology started going backward as none had the chance to advance or evolve their technology, reducing humans to a state of a decayed modern age. The humans live in fear of the demons, seeking only a way out or a way to be safe. However, recently, a group of revolutionaries has started rising underground, forming an army of their own with the goal of destroying the Great Demon Lord. Together with their newly grown special powers and for some even special weapons, they seek to fight against the demons to return their freedom. Find out what will happen in this post-demon-apocalyptic story, the world of Dawn Blade!

Although the world appeared to be normal, one day changes occurred. The 'New Generation' was formed. Young children moving toward highschool started developing abilities. These abilities were the same or shared with gods and mythical creatures. For example one had the abilities of Zeus able to produce lightning, and so on. These were called the 'Irregulars', all sent to 'Sacred High', a highschool created specially for them. This however is not a normal school, as there are no adults around to lead anything. It is run by the students, mainly the Student Council, and forms a battle for survival, survival of the fittest. One day, the supervisors on the outside found something different ... An Irregular Among Irregulars, alias IAI. A young boy that was within the New Generation, yet had no abilities whatsoever. After the entry interview, the youth claimed: "I have no religion or beliefs but my own path." Due to this statement, this youth was titled "The Atheist', put on Sacred High between the rampant gods and myth wielders. Striving to aim for higher popularity ranks to ensure their safety, this was literally a battle to survive and become the strongest. The better your reputation, the less likely anyone would bother you. At the top stands the Student Council, possibly the most rotten out of the school, while at the bottom, the new IAI joins. Does this youth have no actual powers at all? Will the Student Council do something odd? What is the purpose of this school? Find out and explore Sacred High!