Kruthiks (MToF)
Kruthiks are reptilian predators, covered in chitinous plates and spines. Each of their legs ends in a long, sharp claw. And their mandibles are strong enough to chew through stone. As a hive creature, they live in tunnels that they dig themselves, or take over existing cave structures. Interestingly enough, they often let elementals, undead, oozes, and even constructs cohabitate their lairs. Though how such arrangements are made is quite perplexing, given that Kruthiks only speak their own language, and don’t seem to possess any spellcasting or ritual capabilities in their own right, despite having the mental power for it. Still, a vague listing of allies is better than no listing of allies, and at least it can inspire searches for creatures that might be able to serve as backup.
OK, I’m going to say it, Kruthiks look a lot like they would fit in with the Zerg, and their temperament matches that observation. While Gnolls function a bit like locusts, these creatures function more like ants, right down to the hive structure, the tunneling, and the seemingly eclectic group of friends that they keep. Given this similarity, ants would serve as a great source of inspiration for what these creatures should be doing, or even what might be happening to these creatures. Multiple hives coming into territorial disputes with other underground creatures (like kobolds or dwarves), while fleeing from their own version of Ophiocordyceps (the ant-zombie-fungus), would provide a decent low level adventure hook that has multiple resolution paths. Keep in mind, these creatures do have a language and at least human levels of intelligence, so it is theoretically possible to negotiate with them.
Kruthiks come in three different categories for this book: Young, Adult, and Hive Lord. Each category builds upon the options of the previous with a new hook. Making this entry easily truncated.
Young Kruthiks are somewhat advanced low level fodder. At CR ⅛ they come with a low damage melee attack, a climb speed, a burrow speed, Tremorsense, and most interestingly, a way to tunnel through solid rock. Allowing them to pop themselves into existence in any square on a battlemap. They also have pack tactics, meaning they are at their best when they are swarming the same target. It’s also worth mentioning that their Tunneler ability creates a permanent whole that other creatures can use, making it much faster for reinforcements to arrive after the first breach.
Adult Kruthicks are all that, with bigger numbers (most noticeably in the speed and multiattack departments) to match their CR of 2, and the somewhat novel Spine attack, which is a short ranged attack presumably made out of their body parts. While the range is on the short side, it does allow them to fully exploit their climb speed by shooting the enemy from above, preferably while the Younger Kruthiks provide advantage.
Hive Lords are the Queens of the hive. They have all the tricks of the Adults (and thus all the tricks of the Young), with the addition of even bigger numbers for their CR of 5, and an Acid Spray attack. While the logical use of the Acid spray is hurting the PCs, acid can also be used to dissolve most metals that would otherwise stop Kruthiks from burrowing into a secured area.
In the changeover, Kruthiks lost their Keen Smell ability, which was folded into their Perception score.