Gargoyles are beings that were created off of the idea of actual Gargoyles from another system. The first Gargoyle in the Destiny System was classified as both undead and a golem. They are in no way related to Demons, but more akin to Dragons.
Being classified as an undead and a golem, they're weak to both weapons made of silver and gold as well as curses. Thus, using both makes attacks doubly effective. However, being both also makes them even more dangerous.
Typically, Gargoyles' claws and bite are venomous, and there are no known cures for said venom. The venom has been observed to slowly rot away skin over a period of 2-3 weeks. After this time, almost all flesh will have been destroyed, leaving internal structure open. The venom does not kill, but instead causes extreme pain, and will eventually seep into your Soul and ferment it. This Soul slowly leaks from the body of the infected and will begin killing plants and other living things upon being too close.
Gargoyles, despite popular belief, are not usually made of stone. Most have skin much like that of a Futr-Human, being as strong, if not stronger, than steel. This skin is extremely valuable, just like the skin of the Futr. It's light and durable, perfect for rangers and warriors.
As stated earlier, Gargoyles are related to Dragons. Gargoyles use a breath attack, much like many Dragons. Their breath attack is mostly spraying a poisonous gas at high speeds. Due to the speed, it corrodes like acid, but has no acidic properties. The poison acts exactly like it's bite and claw attacks, but must be inhaled to take effect.
Gargoyles aren't typically hostile, unless their nest is intruded upon. Their nests are usually on mountains, tall buildings, or the interior of destroyed buildings. Their eggs are almost perfectly round, and harder than Mithral. Unlike many creatures, Gargoyle hatchlings hatch with fully hardened skin and fully functional wings. This makes survival pretty easy.
Overall, Gargoyles are protective and dangerous. They're rarely around humanoid races, giving no reason to attack other than self-defense.