Crimson Longinus
Legend
So I don't have exact numbers, but I certainly have thought about how common NPCs of various levels are, and what do the level actually mean. I wanted to avoid the Faerûn effect, where there are high level NPCs hanging around every corner, and I also wanted to avoid the Warcraft effect of the world strangely scaling up with the characters. On Artra tier 4 NPCs are super rare. It might be illustrative that it is known that the Archmages of Shimbal are famed of their ability to cast spells of "all the eight circles of magic." Yes, people who are able to cast ninth level spells are rare enough that even the existence of such magic is considered a myth. There are of course handful of individuals of 17+ levels, but they're very rare legendary, or even mythic, individuals.