The exact same thing applies to a fantasy setting, there is no difference. The Necron example I provided is equally applicable to our stone Ushabti discussion. A Skink finds some exotic tree sap in the jungle and notices that when it drips onto stone, the stone becomes brittle and flakes away. Having heard that the Tomb Kings command animated statues of stone, the Skink collects and employs the strange sap as pseudo "poison". Done... just like they described in the Necron passage. That's just one example, you could come up with hundreds of iterations. A bit off topic, but in terms of resistance to impact, stone is nowhere near as resilient as something like steel. Put a sledgehammer to a stone statue and it will crack, break and crumble. Do the same against the same statue made of steel, and you'll have a much more difficult time of it. Sure you can slowly deform it, but it won't shatter in the same way unless it is stupidly hardened. The impact from the dart itself would have a no effect on something like bone, and little effect on flesh. It is too light and is moving too slowly. That's why you wouldn't really expect non-poisoned blow darts to feature on a real battlefield. As for affecting Daemons, who knows. It's a fictional creature so it's up to the author. Many animals have either partial or full immunity to poisons and toxins that would kill other creatures. We get bit by a cobra and we die, while a Honey Badger can tank it. So it is not unreasonable to propose that a Daemon would be immune to it... heck, GW puts forth the very same concept in the Necron passage I quoted (and GW is more of an authority on the subject than you or I). As for the K'daai.... ...I see fire and metal, both of which I feel would be immune to poison. I'm not seeing these vulnerabilities that you speak of. The problem with using fluff to alter official rules is that it is too reliant on interpretation. Every army book builds up their troops, characters and units. Kholek should be able to single handedly crush an entire army, and a Slann should be able to topple an empire with a flick of his wrist. Unless the rules writer has incorporated something from the fluff directly into the game, it is best to maintain a healthy distinction between the two. Another example: "With the K'daai they have sought to do something more, to create a race of beings, half-daemon stuff and half-raging fire drawn from the magma of the deep earth and birthed in the boiling blood of Hashut's burning sacrifices, given form and contained within an armoured framework of articulated iron and rune-stamped bronze" In the fluff passage above, it actually outright states that the K'daai have an armoured framework of iron and bronze, yet in the rules for the K'daai (Fireborn or the Destroyer) there is no mention of an armour save. Ergo, the Fireborn should have at least a 4+ armour save and the Destroyer a 1+ (since it is essentially a fire daemon encased in a giant armoured statue). Fluff-wise it makes logical sense, but game-wise it is rather silly. This type of rules manipulation is nothing more than wish-listing manifested to life. Fun for the person who is manipulating the rules, but not as much so for anybody else. It's either going to lead to an escalation of arms or people refusing to use the made up rules.