When Asgard fell the lords of Midgard took advantage. Before the alien invasion descended, the Lords sent their children to the outer most ring for an experiment.
Vikings raided. All adults were slaughtered. The children were gathered and branded as slaves.
Most of the children died after passing Ringworld barriers and suffering seizures. Others starved, suffering from sped up metabolisms. Only one boy had no symptoms.
Weapons and tools that broke Asgard’s sacred rules were tossed over a ringworld’s edge. Some melee weapons were kept. Oddities with unknown functions, but with at least a blade or other obvious aspect.
The boy did not age. He stayed just shy of puberty for years. It was assumed permanent and allowed him to be unassuming.
He fought bullies and found unnatural speed. Twice as fast for a breath. Four times as fast for a single movement.
Once after five years he touched a displayed sword, a trophy of his capture. The sword recognized him.
As a slave he didn’t have the right to hunt and earn his heartrune. Others that did got powers, but nothing quite like his speed.
A bully, now with a heart rune wanted a rematch. The ageless boy obliged and with his enhanced speed won.
This garnered interest. The village sage examined him and divined that he already had a heart rune and it was responsible for his stunted age and speed. The sage warned he would be killed and advised that he run.
The boy used his speed to steal the sword and ran to the eight Ringworld.
There he disappeared. Over the years sightings kept his story alive.
In the wilds he learned to speed up for longer. He could only now double his speed, but he could do it for hours.
More and more excursions came into the outer Ringworlds. The ageless boy finally joined one settlement as a guide. He was respected, even treated like a normal person at times.
Elves were not unknown and there long lives were a reference for him. He was the human elf.
It was a rumor only. Elves and humans could not breed any more than a tree could with a horse or a flower with a rabbit.
Elves and dwarves were rare because of the shattered Bifrost. No communities. Just stranded individuals.
