Much like my last post, here's a bit of free-floating worldbuilding related to a mysterious, underground-dwelling, animal-related, fantastical sapient species with a tenancy toward covert operations. It's one of those artworks that makes me realize just how far I have to go.
Anyways, my own take here, inspired by some of those old pulp short stories like Kull the Conqueror and such.
Serpentfolk, as presented, are rule-breakingly ancient, driven underground by some great calamity before anyone else had figured out agriculture.
They are all-gifted, as it were, having the speed of fast snakes, the strength and endurance of constrictors, venom at all with a mouth that big, as well as profound intellects and very long life spans. The problem is that they are arrogant, seeing mammalian life as beneath them to point of drawing little distinction between a cowherd as his cattle.
Their long life-spans and high average intelligence foster a tendency towards extremely high education, with most serpentfolk not being considered full adults until their hundredth year, and just about any one of those full adults being polymaths beyond most mortal dreams.
One notable feature of serpentfolk's relationship with magic is a tendency to assume new forms to blend in on covert missions, or to permanently alter their forms to suit their occupation. The warrior pictured above has assumed an additional pair of arms for sake of deadliness, and red scales instead of her native green as a form of martial display.
Serpentfolk's interactions with the surface world, or even other underground-dwellers, tend to be extremely covert, or extremely violent (often both in that order).
Societally, Serpentfolk tend towards living in city-states with palace economies. The arts are highly developed, and learning is a common treasure. Despite all this, such city-states tend to be dens of nearly every evil, oft visited on such sapient mammals as they can capture.