I'm a fan of psionics, and with the release of Dreamscarred Press's excellent Psionics Unleashed, I've been thinking of ways to integrate psionic fluff into the Pathfinder Chronicles campaign setting. These are my ideas - please share your thoughts! I'm especially interested to hear if anyone else has tried anything similar with their campaign.
Blues
Blues are easy - they live wherever goblins do. Psionics Handbook portrayed the blues as a genetic mutation among goblins, while Psionics Unleashed plays them as a separate race from goblins who infiltrate their tribes, spread their genes, and slowly supplant them. Either way, they're easy to implement anywhere in Golarion.
Dromites
These insect-like people feel out of place in a fantasy setting like Golarion with their alien appearance and psionically-saturated culture. I have them as natives of Castrovel, living alongside the lashunta. Perhaps they've established a beachhead colony on Golarion to explain dromite adventurers; given the elves' association with interplanetary travel, Kyonin or the surrounding areas seems like a natural location (maybe in the mountains to the south).
Duergar
The gray dwarves are already established in Golarion. I like to think that the embittered dwarves who were left behind in the Darklands awakened their psionic powers to survive with their drastically reduced numbers.
Elans
Because they are basically altered humans, elans can conceivably be found anywhere in the world. But where did their secret society come from? Castrovel seems the easiest answer, but it could just as easily have originated among the humans of Vudra. Maybe Vudran psions who stole lore from Castrovel?
Half-giants
The half-giants' human heritage makes a Golarion-based origin most likely. I place them in the Windswept Wastes of central Casmaron. In my campaign, they are an offshoot of the Keleshites who intermingled with giants. Their fire resistance is a blessing from Sarenrae, while their psionic abilities are the result of centuries of introspection to unlock their psychic potential.
Maenads
In my campaign, maenads are a subrace of humans and have the (human) subtype. They are native to Vudra and are famed sailors. Their patron deity is Gozreh. The maenads' rage is the result of a curse from a god they had offended, and their divergent evolution from humans comes from ages of physical and psionic rituals to stave it off, centering around the crystal particles embedded in their skin that help regulate their psychic surges. They pioneered the path of the wilder, which was picked up and spread by the Vudrans.
Mind Flayers
Officially, mind flayers don't exist in Golarion; intellect devourers take their place as the iconic brain-eaters. In my campaign, though, they have had a presence in the setting since ancient times. Arriving from the Dark Tapestry in their nautilus ships, the illithids settled in Sekamina and began building their civilization, using orcs and dwarves from Nar-Voth as food and breeding stock.
However, as we know, larval flayers that fail to metamorphose into illithids grow to become neothelids. Perhaps a mind flayer colony was destroyed but its spawning pool was untouched, allowing the larvae to mature into neothelids. Realizing that they were the true form of their species, the neothelids launched a vicious war against the mind flayers, wiping out their civilization. They then psionically altered their genetics to give birth to single, full-grown neothelids rather than litters of larvae that could become illithids and traveled down to Orv for solitude. The few surviving illithids fled through space to Castrovel, where they now have a smaller, much more cautious society, feeding off the lashunta. However, rumors among the drow suggest that some illithids may have remained behind and are planning a comeback...
Ophiduans
Like the dromites, I place the ophiduans (from Psionics Unleashed) on Castrovel, because their expansionist culture would have destabilized Golarion if they existed there. Their culture is also radically different from Golarion's native reptilians (lizardfolk and troglodytes), who are usually highly primitive. They have at least one nation or empire that is in conflict with the lashunta. They may have a connection to Golarion's serpentfolk.
Synads
The synads, from 3.5's Complete Psionic, are an aberrant race who resemble humans but whose brains each host three separate minds who work in concert. I place them on Castrovel. Perhaps the elans were first created from humans who wanted to emulate the synads.
Thri-Kreen
Another WotC-owned creature, the mantis warriors cannot be used in the Pathfinder Chronicles. In my game, though, they are another native race of Castrovel, where they inhabit equatorial deserts as nomadic raiders. Taking a cue from Dark Sun, these marauders may be the primitive tribal outlanders of a larger empire of civilized kreen who live far from the lashunta nations.
Xephs
Given their appearance and great dexterity, I like to think of xephs as distant relations of the goblinoids (but not close enough to have the goblinoid subtype - more like humans and halflings). Their civilization is centered in a great forested canyon in the vicinity of Vudra, where they fill a similar niche to elves in Golarion. Xephs are a common sight throughout Casmaron and southeastern Avistan. As a race of travelers who value artistic expression, Desna and Shelyn are important gods to them.
Yuan-ti
Like the mind flayers, yuan-ti are WotC's intellectual property and can't officially be used in Golarion, where they are replaced by the serpentfolk. In my house campaign, however, yuan-ti are descendants of a secret society of Tian humans, possibly related to Nagajor's Order of the Poisoned Fang. Using psionic lore pilfered from both the serpentfolk and ophiduans, they combined their genetics with those of snakes. They are seen as abominations by the nagas and ruthlessly hunted. The yuan-ti are worshipers of entropy and may have had a hand in Lung Wa's collapse.
