Deep Ones, Kuo-toa and sahuagin

Because I was deliberately creating my very first pass at a bestiary for Dark•Heritage, which later became Dark Fantasy X which eventually became Shadow of Old Night by leaning into Lovecraftiana, I of course included Deep Ones. It also "helped" that I was going through the very first iteration of Cult of Undeath, an attempt to see how I could adapt the Carrion Crown adventure path into something that I could use (it later evolved into simply a Gothic horror themed campaign 5x5 Front with only a few passing nods at an idea that may have originally been in Carrion Crown.) One of the modules in that series was deliberately called "reverse Innsmouth" and heavily features Deep Ones... under another name.

I had to look into the history a little bit of Deep Ones and their D&D analogs to see what was going on. While there are multiple fish people, none of them are exactly Deep Ones until fairly recently, actually. Paizo in Bestiary 5 had Deep Ones long after Carrion Crown was released so that adventure path obviously couldn't use them. While there are many fish-people analogs, the two most notable, because of their use in many adventures, including many classics written as long ago as the 70s by Gary Gygax himself in some cases, and one of them was very explicitly meant to be the analog to Deep Ones, while another is often interpreted also as a different take on the Deep Ones.

The kuo-toa are the specifically Deep Ones-like analog; although they have developed their own history and character somewhat. They've also been posited to be nearly extinct in the oceans, and are mostly expected to be found in the Underdark these days. They are also saddled with the stupidest souding Gygaxian name in the form of their deity, Blibdoolpoolp, but lots of sources here and there since 3e talk about "renegade kuo-toa" who worship the demon lord Dagon; a deliberate nod towards the Deep Ones and Lovecraft. Sadly, they have a normal frog-like reproductive strategy, wherein the most horrifying aspect of the Deep Ones is that people turned into Deep Ones if they came from the right cursed bloodline that had just enough Deep One DNA buried in it. D&D also, as they have done with all kinds of other monsters, has reduced the monstrous and horror elements of the kuo-toa and tried to make them sympathetic in some ways. Major mistake. 

Kuo-toa are also considered product identity, and are not in the SRD. This is no doubt why Paizo didn't use them, when they were the obvious choice; they instead used skum, a less defined fish person kind of thing that is vaguely associated with the aboleths. Another wannabe Deep One, essentially. Skum was kind of a silly name, which may be why they never really stuck, so Paizo eventually created their own Deep Ones directly, as mentioned above. Frankly, I think it's pretty crappy WotC decided to keep kuo-toa and yuan-ti out of the SRD, when both were clearly and obviously just riffing on pulp creations of Lovecraft and Howard in the first place, but whatever. Paizo and Green Ronin and others who wanted to make D&D-like stuff with Lovecraftian nods had to go back to the original source and do it their own way, I suppose.

The other major fish person race of D&D that gets a lot of traction are the sahaugin, or sea devils as Green Ronin (and occasionally D&D) likes to call them. These are in the SRD, so it's curious that Green Ronin, as far as I've noticed, almost never (maybe absolutely never) calls them anything other than sea devils, or that Paizo didn't attempt to use them in the Carrion Crown adventure. This is probably because the sea devils, which look a little bit like green scorpionfish made humanoid, have a bit less of the Deep Ones vibe, being less infused with madness and infiltration, and more just vicious and violent underwater raiders who attack ships and coastal towns alike. Although Keith Baker has said that had he the time to develop it further in his Eberron work for WotC, he was deliberately leaning into Deep Ones with his sahaugin "Empire", the reality is that the sea devils are more like predators than eldritch horrors; more akin to social humanoid sharks than Deep Ones. There's a sufficiently different vibe to Deep Ones, sahaugin, kuo-toa (and skum, and locathah and mermen and tritons, etc.) to keep them separate maybe. As I saw someone point out on a forum years ago, there's more difference between sahaugin and kuo-toa than there is between orcs and hobgoblins on land, and few (other than me, curiously) has ever thought that they should be folded back into a single creature. So there's some call to have at least two different types of fish people, I suppose, and that's what I'm thinking about with regards to Old Night, especially as I'm thinking more and more about the Corsair Coast, where they'd play a role, perhaps.

Now, although I have Deep Ones in my monster list and have ever since my first passes Fantasy Hack m20 and Dark•Heritage m20, to the extent that I have a riff on Innsmouth it's next to a swamp rather than on the coast, and it's snake people that they turn into, not fish people. Because of that, I doubt that the insidious nature of the Deep Ones and their taciturn and sullen collaborators and hybrid offspring would really play much of a role in any of my campaigns; I've got that angle covered already. So something more like the sea devils is more useful to me. But...

I've deliberately consolidated similar concepts into fewer statblocks, and said that just because this statblock can represent more than one creature, doesn't mean that they should be seen as equivalent. My Thurse stats can represent Warhammer style beastmen (the "real" thurses) as well as ogres, bugbears, gnoph-kehs, yeti or Bigfoot. My Deep One stats therefore can certainly do double duty to represent Lovecraftian Deep Ones as well as more action-movie horror sea devils.

Of course, action-movie oriented is perhaps the wrong idea. They can be, or it can be more like the classic creature from the Black Lagoon; which seems to somehow straddle the line between the two ideas; it's more just a creature that attacks and kills people who trespass into its territory, but it also seems inordinately and creepily fascinated with the woman that they bring with them, and constantly targets her for capture not killing.