Aion Kaos' life was nothing special. He was born to an average family, lived an ordinary childhood, and now, as a 16-year-old high school student, lived a mundane life. While you may infer this to be undesirable, seeing as how there is, seemingly, nothing out of the ordinary or unique about his life, Aion didn't think in that manner.
He had no overarching goals to pursue, neither did he have defining ideals, or a burning passion. In fact, he himself believed that if he did not hold the ability to tell the tale which was his life, no one would believe he even existed in the first place.
He didn't believe this to be a bad thing, however. His entire life, he felt no tremendous weight upon his shoulders at any time, due to the fact he never aimed for anything truly great. He wasn't depressed, or anything merely as simple as that, he was simply, in his own words, "not meant to be born into this world."
As he finished school for the day, he heads home the way he usually does, by walking. He never took much caution to, 'look to both sides of the street', because he never thought he'd die in this manner, or, rather, that he wasn't fated to. Nonetheless, as he crossed the street, he had a sudden thought, "How long will this go on for..." This thought would be alarming to anyone with a rational mind, as it isn't something you'd expect to come from an average student.
It doesn't take much of a genius to infer what 'this' was referring to. He felt lost, within life. Not overwhelmed, not saddened, and perhaps not depressed. It was an entirely new feeling that could not be described with words, one which could make one feel so incredibly out of place, as if they weren't meant to be born at that time, or, at all.
As he crossed the street, unbeknownst to him the last time he would, he walked into the path of a rampant truck being driven by someone under the influence, the screams of the people who were helplessly trying to get their words through to the seemingly zoned-out boy, drowned out by his very thoughts. In a mere instant, it all ended.
As the truck collided with his body violently at speeds of over 100 km/h, he was hit with the deadly force of a large, in-motion vehicle, and took his last breath.
In his last moments in this world, he realized what would happen. He wasn't dumb, he knew his life was over, whether he wanted it to come to an end or not. That said, he didn't wear an expression of sadness.
Perhaps this was due to his carefree attitude and view of life; if he died, he was fated to die that day. He didn't frantically scramble to run, or get out of the truck's path. Instead, he accepted his fate, and met his end.
In the next moment, as he opened his eyes, he found himself inside of a luxurious-looking building. In front of him, he saw what seemed to be a 50 or so year-old man, with white hair, and a white beard.
Beside him lays a beautiful young woman, who he, instinctually, believed was his daughter. To his, as well as the old man's sides, there are 12 or so guards wearing steel armor, holding spears that are pointed towards the seemingly 30 foot ceiling, presumably to not disturb or possibly threaten any of those within the room.
As he realized he was most likely not within his previous world, or continent, at the very least, he also realized he was on the floor of what was possibly a castle, meaning he wasn't in the presence of people part of the lower or middle class, as he took notice of the throne the old man sitting on.
Looking down, he saw a fading, white light, in the form of some runic circle that enveloped half of the room's interior. Looking behind him, there were 4 other people, wearing school uniforms just like him, also on the ground.
Taking in his surroundings, he gathered that he was in the most cliché of possible cliché tropes, the Isekai to another world where multiple heroes are summoned to defeat some overpowered creature in another world, because that worlds' forces were either too weak, incompetent or both.
With that said, Aion didn't mind it in the least. On the contrary, he'd always hoped to be in this sort of cliché, since he was always reading Isekai manga, manhwa, light novels; just about fucking anything that could be observed by one or more of the five senses, really.
As he snapped out of his trance-like train of thought, the old man began to speak. "Welcome, Otherworlders. I am King Lonario el Francia, the ruler of the kingdom of Francia." The old man introduces himself as the king of an unknown kingdom, which Aion, and apparently none of the others beside him who seemed to be in the same situation as him, knew of.
After a moment, the King continued speaking. "I know you all may be confused, and I, as well as my daughter next to me, will clear all of your doubts in a second." "Oh, so that really is his daughter. Thank God, if it was his wife or concubine, I was worried it'd be a fucked world." — thought Aion, concentrating on the obviously less important parts of the King's speech.
"For now, I will tell you this. You have been summoned to this world, for the purpose of defeating a tyrannical, evil, aberrant existence, who has terrorized humans for as long as we've lived, and are now finally marching towards our kingdom." The King coughed, before continuing to speak, as if saying the forbidden name of Voldemort.
"He was given a title due to his merciless and cruel ways. The Demon King of Annihilation, Revaneas."