The troglodytes are a group of immortals with thousands of years, who suffered profound mental degeneration due to their uninterrupted life, which started to behave in an almost animalistic way.
At various points in history, perhaps since the emergence of the first hominids, several people bathed in the mystic flames of what would be the city of Kor in the future, acquiring eternal life. As it is known that immortals can suffer damage to the mind throughout their existence, some of them ended up regressing in their ways and behaviors.
In 1236 BC, Bio made his way to the village of the immortals, living among them for five years. The eldest of them would have had sex with her in exchange for showing her a great sacred mystery.
During the Roman Empire, a tribune named Marco Flaminio Rufus set out with two hundred men in search of the source of immortality. Even losing his soldiers, the tribune found the primitives, and also acquiring eternal life, but afraid of ending up in the same situation as them, he dedicated himself in the coming centuries to reversing his fate.
The immortal troglodytes originate from the short story El inmortal, by the argentine author Jorge Luis Borges. The old male Orlando has sex with is possibly an immortal version of Moon-Watcher, the ape-man from 2001 : Space Odyssey.