>>718758718
It actually goes the opposite way.
Marika and her group used to be tied far more tightly to the Nox, as either their ancestor or their descendant (it is kinda unclear what the plan was). With the Nox even being collectively known as "Empyreans". This was mostly cut in development, so what was left is far more vague.
Otherwise, the Numen are described as people that came from 'another world' (with very similar vocabulary to an Isekai story), by this point in the game represented as them typically being from overseas. Travelers that arrived in the Lands Between over time. Them having members that were a part of the Nox society before it was buried is not outstanding or strange.
In this case the Shamans are numen who stayed above ground and built small villages that were raided by the Hornsent. While others became part of Nox society and would later develop into the Black Knife Assassins.
Both are linked to the Gods, either with the Shaman being able to become Godhood candidates, or the Assassins stealing the power to kill the Gods and going on a vendetta against them - this following what the Nox in general once did against the Fingers/Metyr.
