A new world filled with heroes and villains

(The picture is not the city)

Around 50 years ago, a cosmic storm hit earth, and was said to destroy everything, but it just passed through earth, destroying at max a couple smaller cities, alongside some more major cities too. But the storm that was said to mark the end of humanity, instead marked a new start for humanity. At first nothing out of the ordinary happened, but soon the children who were born after the incident started to develop powers through puberty, though it was a small percantage of children, around 0.5% of children had powers after the incident at first, but soon that number climbed to 20%. These children soon started to become heroes and tried to help others. But without darkness, there is no light, and there came the villains too, as soon as they realised what potential they hold. And soon also came the change of organizations and economy(a bit) with need for new gears, equipment, and a training place for heroes, so came the heroes agency, with each country having their own, with their own rules, but the american hunters association dictates the most basics of rules, and they provided the heroes with new equipment and gear to use during their battles.

But of course everything has a dark turn to it, there was once a mighty hero called supernova, who was earth's biggest hero with fire based powers, and the ability to fly, but every hero comes with a rival. And his rival was nyx, able to create darkness wherever she walks, and convert the fear of other's around in a 10km radius around her to enhanche herself in terms of speed, strength, durability, and agility. One day, a war started between Supernova and Nyx and they battled all throughout earth, causing havoc everywhere, until Supernova sacrificed himself by grabbing Nyx and flying out of the solar system with her where he used all his power and exploded accordingly to his name, causing a Supernova. But when an astronaut team was dispatched to the center of the explosion to see what remained of the two, if any, they found the dead body of Supernova, and a piece of Nyx's cape, making the news about her death unsure.

Power levels are pretty basic, with E, being the lowest, and than D,C,B,A,S as the top, And beyonder for those who are way more powerful than S-ranks, like Supernova or Nyx, who were the only beyonders ever in history.