Demons and angels have been at war with each other for over 3,000 years. The Angels reside in heaven so that they are able to watch over the humans, while the demons made their home in the underworld. Angels constantly protect the humans that the demons play harmless pranks or torture to get the energy of 'hate.' Hate is the only energy source that works in the underworld with it taking the place of electricity and other small necessities. The Angles gained the humans on their side, establishing a role as gods and protectors. With humans on their side giving them the unending power source of love, they were soon able to turn the tables and almost fully overpower the demons. With humans now on the side of the angels, it severely enabled the demons from forming contracts with humans to gain hate, making the economy of the underworld steadily decline. Due to the rapid decline of contracts , the painful reality of losing the war slapped the demon king in the face. Soon, the once buzzing metropolis of the Underworld soon became a deserted wasteland, where only the nobles and king could live without worry.
There are several classes of demons within the realm of the Underworld. Minor demons, are simple foot soldiers and are commonly the ones human refer to. They have small rounded horns and a spiky tail, but unlike the higher classes of demons they don't have wings. Several of the more prestige demons like Vampires, Werewolves, Succubi, and King Mephisto all belong to the noble classes. Anything below them were simply considered minor demons, since most of them had a low amount of magical power unlike the nobles. Eren Jaeger was one of those mere minor demons.
Eren was a normal foot soldier, slightly notorious for always getting into fights and the almost annoying amount of hope that the demons would win the war. He was simply performing his daily duties when one day his superior handed him a scroll with his first mission to go to the human world. Eren was so excited that he spent almost all day bragging and ended up staying awake most of the night also. The next morning he quickly got dressed and slowly put on his 3D maneuver gear straps on before placing the actual machines on his sides, securing them with more of the straps. After he was done he excitedly took his mission scroll of off the table and walked out of the shared bunker.
Eren hastily walked to The Portal of Time located on top of the wall Maria. He enjoyed the sight of the beautiful, red moon that had a breathtaking glow to it. When he arrived, he happily showed the portal keeper his scroll and quietly stared into the dark black circle that was the portal. He gulped, knowing that once he stepped foot into the portal he would be falling. Eren took a deep breath before he jumped into the black abyss. He almost screamed as he felt himself fall helplessly deeper and deeper into darkness so dark that even he as a demon couldn't see anything.
In a matter of minutes he could see the human world begin to take shape beneath him. Eren's speed accelerated as gravity pushed him down further to Earth. As he reached closer and closer to a city he skillfully prepared himself for landing. Once he was between two large buildings, he let high speed cords shoot out of his gear and latch onto the brick buildings. The cords bounced him up and down slightly as they held him there in midair. Eren took a deep breath to calm his nerves before he finally began to take in his surroundings.
Eren was awed as he looked up and saw what looked like millions of glistening dots shining in the inky, black space he fell from. He vaguely remembered them being called stars. Eren recognized the white moon that shone brightly in the center of the space, and stared up at it for a few moments before he remembered his mission. He had to find a human to form a contract with and grant the human the false reality of actually granting their wish.
Almost any wishes made with a demon were made out of magic that only lasted a day before everything turned completely wrong. Eren sighed to himself as he looked around and there was no one in sight. Well, at least he seemed to be in a fairly big city so finding a human shouldn't of been a big problem. The only problem was if he had the unfortunate luck of finding an angel. In that case he would try his best to cut off a wing, but that was seriously hard considering they could simply fly out of his range and shoot him with their magic.
Eren flew around the city for a little while before he found a useless human girl carelessly chatting on her phone as she walked alone at night. He slowly crept up on her before he revealed his presence. Eren almost laughed when she was so shocked she fell backwards.
"Hello, I'm a demon," Eren stated with a slightly wicked smile. The girl screamed in fear but luckily no one was around to hear her. "Calm down, I'm not going to hurt you. I simply want to form a contract with you." She slowly regained her senses,"A c-contract?" Eren nodded and smiled softly to show her that he was basically harmless,"I will grant you one wish. Anything you want, if you form a contract with me." He put up a finger to emphasize that she had only one wish. She nodded and began to think quietly to herself.
Eren smiled at such easy success on his first mission, he managed to persuade this human chick within a matter of minutes. He might even get promoted for doing so well! Or at least that was what he thought before he was kicked into the ground. Eren yelped slightly in surprise, unaware of what was happening. By the time he managed to get the unknown attacker off of him his prey had already fled. Eren glared up at whoever attacked him, his eyes widening in surprise. There looking down at him was an extremely short archangel staring down at him, clearly unamused. He gulped slightly before he then got the worst beating of his life.