Appearance & Physical Traits:
These strange creatures appear to be stone statues. Their form only has these thing in common- they have a head, two arms, normally clawed ones, and two legs and they all have wings, usually either bat or bird wings. These wings enable them to fly, despite the fact they are made of solid stone. Most commonly, the stone they are created from is marble or granite, but it does vary immensely. This makes them very hard, though not impossible, to damage.
Skills & Abilities:
They are all capable of flight and are supernaturally hardened so they are difficult to injure. Some of the older ones have an additional magical ability as well. This ability ranges from being able to propel stone spurs from their body to absorbing and releasing heat, though many others are possible. Invisibility and intangibility are, fortunately, unknown amongst them.
Birth, Life & Death:
Gargoyles live a long time, eventually dying when they are so severely eroded that they can no longer function. This can take several centuries, but they usually die long before, when they're too badly eroded to properly defend themselves or can't see and fly into something more solid than they are.
They do reproduce, which is worrying. Whenever a gargoyle finds a moderately round stone between the size of a human's fist and the size of a human's head. This is placed in a nest of debris which the gargoyle builds wherever it can and incubated for several months, up to about a year. During this time, it will grow to the size of a human head and turns completely spherical- the length of time it's incubated varies upon the stone's shape and size- the closer it is to the ideal shape and size to begin with the less time it takes. Whilst the stone is incubated, it is slowly imbued with magic until, eventually, it hatches and a new gargoyle is born, one that will steadily grow for several months until it reaches adult size and goes to build its own nest, fighting for prime nest-sites. Often these fights result in one gargoyle being reduced to a lifeless pile of masonry.
Fortunately, the scarcity of rocks of a suitable size and shape often limits the population size, and internecine fighting inevitably claims some of the gargoyles in bouts for territory, plus ill-considered fights with a superior foe claims more.
Gargoyles are incredibly stupid, incapable of recognising any foe as superior until they are at the least badly crippled and often dying. They are also very territorial, and will attack anything they see in an area they consider their territory. In Inside, this 'territory' mostly consists of the Blue Zone's rooftops, though smaller splinter colonies have been founded elsewhere in Inside.
Also, I largely presume that occasionally Remnant stops the population from spreading too far or becoming too large.