As was predicted time and again, human arrogance and meddling with the natural order was the end of our civilization.
Advancements in DNA manipulation led to the introduction of high society treatments. The rich and famous found themselves in sleek, idealized, healthy bodies.
Meanwhile, a counterculture in the lower classes took root, favoring inexpensive treatments which developed strength and sturdiness at the expense of traditional beauty.
Those neither rich nor given to rebellion began referring to the others as elves and orcs, after the stories they were told in their childhood.
War was changed forever. First with super soldiers in mechanical armor, followed by hulking winged living weapons.
Nigh indestructible beasts armed with size, strength, all sorts of weaponry coded in their genes.
It’s not known what glitch in their coding caused them to turn on their masters, but when the war was over they did exactly that.
All humankind hid for years from their own weapons, which eventually settled down, claiming their home military bases, guarding them to this very day.
Bases filled with armor, weapons, vehicles.
Humanity was knocked back to the dark ages. With the historical record destroyed, all memory of machines, biology, and geography faded.
Occasionally, someone finds a machine.
Occasionally, an enhanced ability gene is expressed.
These are seen as magic.
And to the scattered kingdoms speckling the map, they are.