I'm going to do something highly unusual (i.e. "bad") and start this post by looking at the advertisement at the end of the book. Coming soon is Beyond the Prism Pentad and it promises major changes to the Tyr region. The Dragon is dead, as are three of the six remaining Sorcerer Kings, and the terrifying new threat that's responsible for this carnage is . . . safely locked away once more, presumably by NPCs in book five of the pentad. We've finally reached it - the border between the boxed set's initial compelling pitch and the metaplot rigmarole. I have to say, I've been dreading this. It's just too much change, too far offscreen. Plus I don't think much of Rajaat as a threat. My understanding is that his goal was to genocide every sapient species on Athas except the halflings, which is not only boring in its own right, but reinforces the assumed ubiquity of orcs and gnomes, et al by providing an explanation for their absence. Just let Athas be its own thing, TSR! It doesn't actually gain anything by being tied into the larger brand.
Luckily, Thri-Kreen of Athas by Tim Beach and Dori Hein is mostly metaplot neutral. You could use the bulk of it straight out of the core. But then, there's a bit about the Thri-Kreen population in Raam openly eating elves and getting away with it because of the chaos on the streets, and that doesn't quite track unless Abalach-Re is dead. However, it mostly deals with the insect people who live deep in the desert and don't really stay abreast of current events, so it has a kind of timeless quality.
Except when it's setting the table for its own metaplot. There's an empire far in the north that was previously inaccessible due to a large mountain range blocking the way, but a recent earthquake has created a navigable rift in those mountains, and like all empires, the northern mantis people are looking to expand.
It's an interesting potential conflict, and a good look at a hitherto undetailed part of Athas, but it suffers from the logic of the metaplot - it felt like a lot of stuff was being held back for some future adventure. The book even comes right out and says it, "future releases will deal with the civilized tohr-kreen and other creatures of the northern lands beyond Tyr" and presumably, that's why, if the PCs decide to try and follow the tohr-kreen back to their homelands, they "are not meant to pass the barrier in the Rift at this time."
Hey, if you've got something to say to me, just say it. Do you not realize how annoying this is going to be decades in the future when those supplements are long out of print and only available for hundreds of dollars? Or do you think that summer is going to last forever? This just feels like a tease.
Of course, maybe it's okay to tease the tohr-kreen in a book that advertises itself as being about the thri-kreen, like, I don't know, it's a related, but not identical subject matter and so it gets touched on, but not fully detailed. Maybe if they gave me the full scoop on the tohr-kreen and their imperialistic society, that would scarcely leave room for the nomadic hunting packs of the thri-kreen.
Which brings us to the touchy subjects of species, race, and culture. Namely, what the fuck are we even talking about with this tohr-kreen business? I always thought that "thri-kreen" was the name of the species. And in 1982, when they were first created, it probably was. But we're in a new edition now and old canon is being stripped down to be repurposed into new. "Kreen" means "people" and "thri" and "tohr" mean "nomadic" and "settled" respectively. Which leaves us with no good name for the species. Except that we get six of them - six separate types of let's-call-them-"kreen" with different physiology and appearance. They all have different colored chitin and different variations on their mandibles and antenna and that's fine as far as it goes, but then the text volunteers abstract information like how the Jeral are "cultured" and the J'ez are "militant" and the Tondi are "reclusive" and it starts to feel a little uncomfortable when the book is also cagey about mixed parentage, saying "though interbreeding is possible, the physiology of members of different species differs enough to make successful procreation rare."
That just feels like the worst possible implementation of diversity to me. Maybe making them fully separate species would be worse, but that's hard to say, because this version still has all the implications that race-mixing is unnatural, but in a package that feels more like human races. Or maybe it's something that should feel like human races, but exaggerates their physical differences, making something that should be simple needlessly fraught. So, to sum up - yes to more diverse kreen, no to making their differences anything more than cultural and/or cosmetic.
So, about the Tohr-Kreen. Their empire is made up of all six sorts of kreen (and three of the six types also have individual nations of their own, though all of them have diverse residents), and it is implied that the thri-kreen of the Tyr region were a subjugated race (the To'ksa) and their overseers (the Jeral) who split away thousands of years ago. Possibly they escaped, possibly they were a failed colony, but the two groups were isolated enough from each other to follow completely different paths of social development.
Or, at least, they would be, were it not for the species ancestral (the book calls it "racial") memory. That's the explanation for why these completely isolated groups can share the same language (they learn it almost as soon as they are born), why thri-kreen NPCs don't necessarily need class levels to pose a threat (what, you thought those Monstrous Manual stats were a convenient shorthand?), and why, when thri-kreen explore up north in the included adventure, they get ominous warnings at crucial points in the plot.
I don't hate the idea of a species driven by ancestral memory. It's a speculative fiction concept with a lot of potential, but it's deployed in a pretty perfunctory manner here. It mostly exists as a substitute for the childhood education that becomes impractical for a species that lives 25 years. It gets into some good territory, with the thri-kreen preferring to lay their eggs in graveyards, in hopes of unlocking more of the wisdom of their ancestors, but it stops where it should start, and never really creates an alien psychology that explores the tension between this indelible cultural legacy and the short and brutal life of the present.
Similarly, I thought the "clutch-mind" was an idea that could have been polished into something special. The thri-kreen have this hormonal and pheromonal process by which they bond with other intelligent creatures, usually, but not exclusively thri-kreen, and subsequently become exceptionally loyal to and protective of the bond-mate. I enjoyed reading about the ways that differing expectations in relationships made communicating with humans difficult. I just wish there had been more about personality conflicts inside the clutch-bond, different thri (or tohr)-kreen cultural expressions surrounding the bond, and philosophical schools that tried to make sense of the bond and its relation to individual freedom and identity. A human might balk at implementing what amounts to self-imposed mind-control (the bond "transcends alignments," forcing kreen to act lawful and good towards clutch mates even if they are chaotic and evil by inclination) just to fit in better with their friends, but the kreen can't seem to live without it. What does that mean?
Overall, I'd say that Thri-Kreen of Athas is a decent sourcebook. It contains the seeds to quite a few good ideas and I can't entirely blame it for not having enough room to let those seeds fully blossom. I wish there was less metaplot and more philosophy, but I can't necessarily count that as a flaw because if I had my way then every rpg supplement would be nothing but speculative noodling. I'd use most of this material in a Dark Sun game, even if the words "prism pentad" fill me with a nameless dread.
Ukss Contribution: The kreen don't sleep. They are biologically incapable of it. But the detail that most amused me is that they also don't understand it. They think it's some kind of character flaw, like mammals are just choosing to sleep because they don't want to be active all night. That sort of stubborn misunderstanding is my favorite part of playing a non-human character. I probably won't have mantis-people in Ukss, but there will be some kind of unsleeping creature that is under the mistaken impression that everyone else is just super lazy.