These people had no spoken language, or culture, except for the use of fire and stone weapons. However, they held a respect for the land, and for other living creatures, that impressed the sky Spirits. Because of this, the Sky Spirits decided to gift them with a genetic bonding so they might thrive and protect their planet. The character traits infused in the inheritors have in reality been speculated to be linked to a variant in Dopamine receptor D4 which indeed started spreading around 40,000 years ago.