Along with the aarakocra, the thri-kreen are one of my favorite non-standard races to play. Unique and alien, thri-kreen provide for unusual roleplaying opportunities and unusual flavor at the table. The challenge? Thri-kreen are a powerful PC race (see Behind the Development below). Converting them to a standard PC race while maintaining their flavor and popular, race-specific powers was a challenge and even with this conversion DMs should consider before allowing them in their campaigns. If used, DMs and players should play up the thri-kreen’s social disadvantages as much as possible, including limited communication and insight into humanoid motivations and feelings. Though I follow Monte Cook’s design rule that “fluff does not balance crunch”, if you have decided that thri-kreen are usable in your campaign, you can use these disadvantages to build interesting stories and social interactions while balancing some of their physical benefits. Remember that 5th edition emphasizes combat, exploration, and social interactions in equal balance.
Thri-kreen are nomadic, insectoid humanoids typically found in deserts and savannah. They communicate with a species-specific combination of clicks, body movements, and antennae waves, though it is suspected that pheromonal communication allows for more subtlety than most humanoids can decipher. Though non-thri-kreen can learn to understand the basics of thri-kreen communication, it’s impossible to speak. Most thri-kreen understand Common with the same level of understanding. Unless a thri-kreen has spent significant time with non-insectoid humanoids, they make all Insight and Persuasion checks at disadvantage. The same is true of mammalian humanoids when dealing with thri-kreen.