His'kilooi Earth, also known as the World of Heroes, the Planet of Supers and nicknamed 'Superpowered Planet' and slurred as the 'Viral Mutants', is a version of Earth where the Human population developed effectively superpowers (or Quirks) via a Retro and Mutagenic Virus called the Abomination Virus, and once started out as a small portion of the overall population has grown to included more then 80% of the total population as of 2416. The planet's technology and culture has, in some ways, regressed, as a direct result of these abilities manifesting, causing instability in the wider planetary society for a period of time infamously referred to by its' inhabitants as the 'Second Dark Age' as society had to adapt to these wildly different abilities showing up and lead to Technology to stagnant and in some ways, regressed to a degree. Because of this, the planet's technology and culture is more in line to that of an Earth in the early 21st century rather than an Earth in its early 23rd century, as the need for effective and advance technology (especially those needed for interstellar travel) was pushed to the side for more pressing needs, like methods of building quirk resistant structures and materials.
Another oddity of this planets' society is the odd laws regarding quirks, as instead of law enforcement being allowed to use their quirks in their line of duty, individuals know as 'Pro-Heroes' have the ability to use their quirks to aid the wider society if the need arises, causing many off-His'kilooi Earth to question this and even debate the effectiveness of such policies.
In 2419, the Abomination Virus's sentience reawaken and spread until more than 50% of the total population, all of whom were quirked, was turned into its' thralls and out of the remaining 50% of the population that did not succumb to the Virus's reawakening, more than 25% of that was killed in the resulting outbreak. By the end of the outbreak, the planet's population declined to a mere 25% of its' original population, devastating the planet for generations and forced the Allied Assembly to place the planet under a state of martial law until 2530, when the planet was stable enough to govern itself again, but the scars from its' horrific outbreak still scars many of its' survivors to this day.