A couple of months ago, a reader asked me to take a look at the spawn of Kyuss in Volo’s Guide to Monsters. Reader, I hope you’re not too disappointed.
Both the flavor text and the ability contour tell us the same thing: The spawn of Kyuss is a largely mindless brute. Its Strength is very high; its Constitution exceptional; its Intelligence, Wisdom and Charisma dismal. This is a creature without any flexibility or independent judgment, or even much of a self-preservation instinct.
As an undead being, the spawn of Kyuss is driven by a compulsion—in its case, the desire to spread its parasitic infection to other beings. This is all the spawn of Kyuss does; it’s all it can do. Other than its attack actions, all of its traits are passive. One of its attacks, Claw, is just an ordinary melee attack that happens to do some extra necrotic damage. The other, Burrowing Worm, is an attempt to infect another creature by propelling a parasitic maggot at them. If the target fails their saving throw, the Burrowing Worm continues to deal damage to them. The spawn of Kyuss’s Multiattack action comprises two Claw attacks and one use of Burrowing Worm.
These are wind-up-and-let-go monsters. They have no capacity to distinguish one opponent from another. They have no reason to stop doing what they’re doing. They’re not beings as much as they are hazards. No judgment on the DM’s part is required. Just aim them at the player characters (or some non-player characters in the PCs’ vicinity) and let them do their thing.
Sorry, reader. The spawn of Kyuss is boring.
Next: cadaver collectors.