Hmm, has there been a newer updated version of the Conan Exiles PFD lately. There is a glaring copy and paste error I just noticed as I was reading the book.
On Page 96, the Sand Reaper and the Serpent Man Doom Spends are the exact same and reference the Sand Reaper abilities.
I hope that the PDF copy I have is the pre release version, prior to printing…
My latest version of the PDF is from March 11th. And this has the error above regarding the Doom spends.
Gosh darn it… 
Who would be able to tell me what was supposed to go in that spot?
The writers are (per Credits page): Richard August, Jason Brick, Danielle DeLisle, Jason Durall, Benn Graybeaton, Tyler Omichinski, Matthew John & Adam Thompson
Maybe one or more of them are available on this forum?
Why not just replace “sand reaper’s sting” with “serpent-man’s envenomed bite”? Maybe that’s the only copy/paste error.
The Serpent-Folk from Horrors of the Hyborian Age have no Doom Spends at all given.
They are Nemesis-type NPCs with higher stats, but basically the same abilities as the Minion-type Serpent-Men from the Exiles book.
Cause I do not think that it fits… well, not to me anyways.
In an early draft for the backers, the Ghostly Slave ability was not a special ability, but a Doom Spend, as it costs 1 Doom to activate.
The Serpent-Men in the Exiles draft have the Special Abilities “Nightvision” and “Familiar” listed. The latter of which I find not fitting at all for a Serpent-Man, and it is incorrectly listed just as “Familiar”, not as “Familiar X”, with a number giving the number of additional d20 this ability provides for supporting a sorcerer in spell-casting.
Both those Special Abilities were dropped from the draft to the version from March 11th 2020.
My explanation would be, that the Ghostly Slave ability should be considered a Doom spend, as it costs 1 Doom.
Though, then no other special abilities remain to be listed for Serpent-Men.
Thanks Frank, as usual. I suspect you are on the right track.
But I am curious to know what the actual Devs say it should be.