Zero no Tsukaima - Volume 4 Chapter 7

Kellen Woods grew up never knowing a normal world. By the time he could walk, his mother and father had already sealed several serious gates that threatened the safety of his hometown. By the time his sister was born, they were famous worldwide.So the world held their breath for when Kellen and his sister came of age, waiting to see what kind of power they would awaken.His sister was just like his mom, same power, same class, while Kellen, woke up one day to find out what it meant to be special in a family the world watched. But in the worst way.Awakening weaker then your powerful parents wasn’t unheard of, but when your younger sister awakened at the same class as your parent, anyone would feel inferior. And Kellen, never one to ask for hand outs, left the comfort and safety of his hometown to become better than the weak brat everyone thought he was.Kellen went to the front lines, to where the gates normally broke out. From there, Kellen worked hard, and then worked some more until no one could doubt that he was good at his job. He got so good that even with his lower class, people would still hire him to help. But Kellen never took it to heart. He had learned a valuable lesson on the front lines. Classification only meant shit if you walked back out of the gate. Otherwise, shut your mouth and listen to those with more experience. They determined who made it out alive or not.But Kellen was tired now. He had gotten everything out of his system, and the fast paced life on the front lines didn’t suit him anymore. Now, he wanted to go home, buy a house, maybe find a nice man to settle down with, and live a normal life.All the while, the yellow eyes he’d met on the front lines haunted him, no matter how much he tried to forget about them.Especially since the Esper they were attached to refused to let him go.

Years ago, Earth was indoctrinated into the “System.”Earth was not the only place with the System, however. With the System came the other races, Invaders. The Invaders had one goal, to obtain ownership of this new habitable planet. This created a bloodbath, and for years the war raged.This didn't really have much to do with Derek. Derek was kind of a loner. Yeah, he enjoyed the occasional chat or drink with others, but he never stayed in one place too long or really got to know anybody new.Derek did happen to be rather strong. After the years of fighting monster and Invaders alone, he had become quite adept at surviving. One thing that helped keep him alive was his refusal to get involved with others. He rarely cooperated with teams.One day, Derek broke his rules and decided to lend some help, as the mission didn't seem too hard. He should have stuck to being alone.

Throughout this current life of mine, I will pay no attention to my past lives, nor will I seek future lives. I wish to live vigorously, to pay back debt of gratitude and fulfill duty to avenge, to defeat valiant heroes from all species, and to proudly laugh at all the Gods and Demons of the Six Path of Reincarnation!

- Description from Novelupdates

It was in the year 2800 of the Midgard calendar. Back then, there was a Overlord who once reigned supreme and had reached the very brink of subduing the world.