Nystylvrn (nih-sTIHLL-vern)
"Don't travel at night unless you have to. And if you do? Do it on foot. No point bringing a mount if it'll get you both eaten."
Star Terrors. Bloodrays. Night Swarmers. The Winter Scourge. The Hunger of the Dark.
Nystylvrn are a species of rky ray that swarm in huge numbers and prey upon large mammals. They are active only during Dusk years on the northern edge of the Sanori grasslands. They can fly completely silently, turn almost invisible in the dark, and can strip a horse to the bone in an hour.
Basic Information
Anatomy
Nystylvrn are about a foot long and weigh around four pounds when their stomachs are empty. They are capable of consuming enough meat to double their body weight in a single feeding.
They have short, angled sails that taper to razor-thin edges. Their sails tear often but heal quickly, so they are often seen with many nicks and scars. Their sails are optimized for speed. Nysylvrn can tuck their sails into their teardrop-shaped bodies and dive at frightening velocities.
They have small mouths lined with pointy, serrated teeth designed to strip flesh from bone. Their bite strength as individuals is not particularly powerful, and they are only capable of biting away tiny bits of meat at a time. In numbers, however, this quickly becomes deadly. They have a second row of teeth tucked behind the first, which will move forward to replace any teeth that are lost.
Perception & Sensory Capabilities
Their eyes are large and placed on either side of their head. They have near 360-degree vision. They can see distant objects quite well but are near-sighted. Their eyes can detect wavelengths on the infrared spectrum, which allows them to easily spot warm bodies, even in the dark. They rely on their spacial awareness to navigate around objects that are close to them. They also have an advanced sense of smell, which they use to track potential prey, navigate to their home perch, and identify individuals within their swarm.
Genetics and Reproduction
Nystylvrn reproduce sexually and mate once at the beginning of spring. After mating, the swarm will fly into the forest. Females lay their eggs underneath the bark of fir trees. They lay up to a hundred eggs, each no bigger than a quarter of an inch in diameter.
After the eggs are laid, the Nystylvrn swarm will take flight again. They will continue to hunt until the daylight grows strong enough that they can no longer fly anymore. Then they will eventually become grounded, and then food for ground-dwelling predators.
Nystylvrn eggs remain dormant for the majority of the Dawn year. Near the end of the Dawn year, they will begin to consume their yolk and grow. By the beginning of the Dusk year, the eggs that survived will have swollen to nearly six inches in diameter. At this point, they can be spotted from the ground as round, blueish growths crowding the upper branches of fir trees. Sometimes there are enough eggs on one branch to cause it to sag or even break. The fallen eggs quickly become food for scavengers.
It is not known exactly how the eggs sync up, but on a bright night at the beginning of the Dusk year, every egg on the same tree will hatch at once into a fully developed adult Nystylvrn. They immediately take flight in search of their first meal. After all of the fertile eggs hatch, the adults naturally divide into swarms of a maximum of forty individuals.
Ecology and Habitats
Nystylvrn spend their nights patrolling the moonlit skies of the Sanori grasslands. They prefer these hunting grounds, as the wide open space makes it difficult for their prey to hide.
When the suns begin to rise, the swarm retreats into the forest, where they will perch amongst the trees. They are careful to spread out their numbers so that they cannot be easily detected. Nystylvrn rest during the day and awaken at night to continue their hunt.
Dietary Needs and Habits
Nystylvrn are strict carnivores. Their diet consists of 100% raw meat. They do not need to feed every night. A large mammal can keep an average-sized swarm satiated for up to two weeks. After a good meal, the Nystylvrn will stay perched in their trees for several nights to allow themselves to digest. Their waste products are very beneficial as fertilizer for the trees that they rest in.
Nystylvrn prefer ungulates like placeholder and placeholder as prey. They don't often attack people unless people are accompanied by a larger animal, which they often are. Nystylvrn are also attracted to sources of heat, as they mistake it for a large meal. It is unadvised to carry torches with you while navigating Nystylvrn territory.
Behaviour
Nystylvrn are not very intelligent and don't know much else besides hunger and violence. They spend their short lives soaring from meal to meal and tree to tree. Despite the myths, they are not capable of grudges, do not remember faces, and do not have any moral reasoning as to who they attack.
They are not completely stupid, however. They can be fooled temporarily by various tricks, but the same trick will not work as well on the same swarm the second time. They rotate between patches of forest to avoid predation, and they are keen enough to notice if their favorite perch has been compromised. They are also aware of when they have bitten off more than they can chew, and will retreat if they encounter too tough of a fight.
Piranhas with wings ARE worse than normal piranhas, it seems.
At least they're only around every other year!