Population Migration / Travel
By this time, Frithitt inhabited the entirety of Frith. The split between "Overlight" and "Underdark" Frithitt occurred around this time.
During the last ice age, Frithitt began to spread out of the deep caverns from which they had evolved and up onto the bluffs of their craggy planet, migrating by waterway and hilltop alike until all corners of the planet were open for settlement. As they spread, the high-elevation "Overlight" Frithitt, of dark pelts, began to differentiate visibly from the light-pelted "Underdark" Frithitt. Despite the claims of some, they are not separate species or sub-species.