Appearing similar to the more common gargoyle, kir-lanan had huge bat-like wings and a muscular humanoid form that was covered in fine scales. Their skin color generally varied in hues ranging from dark blues and violets to black, although kir-lanan could sometimes be found with skin colors of brown, gray, green, or even dark red. Strikingly, the kir-lanan had hard, pointed teeth and claws with short horns cresting their temples.
Since their arrival in 1358 DR, the kir-lanan held an unrelenting enmity towards all deities. This dislike of the gods was such that the kir-lanan never worshiped any of them and consequently never made use of divine magic.
Kir-lanans' bodies were infused with negative energy, enabling them to enhance their natural attacks to damage and weaken living creatures. The presence of this energy within their bodies also had the unusual consequence that they were affected by negative and positive energy in much the same way as undead, despite being living creatures: they suffered injury from sources of positive energy and were healed by sources of negative energy, such as the touch of a fellow kir-lanan. They generally shied away from displays of positive energy, such as a cleric using their power to turn undead. They themselves had an ability to rebuke undead, but were completely incapable of casting divine spells or utilizing magic that entailed positive energy.
Kir-lanan preferred to attack from the air, and would fight with their claws rather than weapons, although they were sometimes known to enter battle with them. Since negative energy infused their bodies, a mere touch would allow them to administer deadly attacks, and some developed the power to project this negative energy with their words.
When they first appeared in the mid-to-late 14th century DR, kir-lanan generally disdained working with others, even among their own kind. When they did band together, these were in small groups—which they referred to as "wings"—led by the strongest among them. These groups were liable to dissolve and reform as the kir-lanan constantly vied for power between themselves. The coming together of a wing was generally when breeding occurred. No social distinction was made between males and females in their culture—only power was prized as a reason for respect—and it was invariably the weaker of the two parents who raised a child.
By the late 15th century DR, kir-lanan society had become much more orderly and complex, largely as a conseuqence of coming under the influence of the goddess Shar. They lived in settlements known as rookeries, and adhered to a strict caste system. The lowest caste were known as "wings", and it was those who displayed stealth and cunning—rather than raw power—who were elevated to the second caste, known as "eyes", who served as spies and assassins. The highest caste, known as "voices", received the will of Shar to communicate to the rest of the rookery.
Kir-lanan appeared in Faerûn during the Time of Troubles in the Year of Shadows, 1358 DR as a by-product of the deaths of the gods Bane, Bhaal and Myrkul. The divine and negative energy released from these deities' deaths caused several hundred kir-lanan to be spawned into existence. They existed outside of divine influence, and were actively hostile to all gods and their followers, whom they called "godslaves."
However, their hatred made it possible to manipulate them, and gradually they came to form an alliance with and ultimately serve—ironically—a deity. Beginning in the Year of Wild Magic, 1372 DR, the church of Shar began making overtures to the kir-lanan, proposing that they alone had the will and desire to make war upon all other faiths, not unlike the kir-lanan themselves. They succeeded in coaxing the kir-lanan into service, drawing them in with Shar's doctrine of "ultimate dissolution." By the Year of the Ageless One, 1479 DR, the entire kir-lanan race served Shar, with their leaders being those who received her commands and their numbers being scattered across Faerûn to assist her faithful. Ironically, they had become "godslaves" as much if not more so than most other races.
- Ghindul, leader of the Howling Wing in 1372 DR.
- Phaikkul, leader of the Screeching Wing in 1372 DR.
- Kzntharris, an emissary to the chruch of Shar in 1372 DR.
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