Wyverns are quite similar to kul in the aspect that they have wings, a tail, a long neck and an overall lizard-like appearance. However, there are a few key differences. Wyverns only have four limbs instead of six, which are their legs and wings. Instead of their forelegs they walk on their wing joints. Their tails are long and muscled, making for a good counter weight when walking. Overall, wyverns prefer flying with their speed-oriented wings to walking, as they aren't really fast walkers at all. A forest wyvern is roughly 1.8-2.2 m (5.9-7 ft) tall at the shoulder, while in their normal walking posture. Females and males are the same size on average and differentiate only in their scent and the fact that females have a tail that becomes thicker from the tail base on for a bit before narrowing down to a tip, giving it the shape of an extremely elongated tear drop.
A wyvern's neck and jaw are very strong, so it can keep a grip on things and climb akin to how a bird may. The neck is also quite long, which makes it possible for them to snap at enemies in a fashion similar to that of a snake. In order to make walking easier and leaping possible, the hindlegs of a wyvern are very powerful. Thanks to paw-like growths on the wing joints, walking on the wings is a bit easier than one may think, however, it isn't nearly as efficient as using proper forelegs to do so. Should a wyvern manage to somehow cling to an opponent's back or belly, then it would attempt to tear them open with the raptor-like claws on their strong legs. It is usually a death sentence to be pinned by a wyvern even for a Trezkul, because their talons will easily tear through their hide.
Covered in green to brown scales, the forest wyverns are naturally camouflaged in their forested environment. Markings like stripes, dots or splotches enhance their ability to hide among trees and underbrush greatly. Even their claws and horns are of a dark color, making them as hard to spot as the rest of their body. Wyverns grow more horns the older they become. They begin at two, but some grow as many as ten total. They grow an equal amount of horns per side of the head. The horns tend to not grow very long or thick, so they are not a hassle to the wyvern. If they were longer, they would get stuck in the canopy of the forest. Their heads are very narrow and angular, allowing for a precise bite that allocates the force of their strong jaws on a small area, which allows them to even dig their teeth into the gaps between an ironhead's plates.
The color of their eyes can only be a hue of brown. Being predators of the night, the eyes of a forest wyvern can see well at night, naturally enhancing remaining light to improve vision. Wyverns lack proper ears and only have the reptilian ears that most species of kul have, so their hearing is not above that of a lin. Yet their sense of smell is only rivaled by that of a kul; a forest wyvern will easily sniff out prey and threats alike, then proceed to chase down the former and fight or flee the latter.
Since they have to compete with Trezkul for living space, the forest wyverns have evolved a resistance to their venom. While it can still kill them, they at least have a chance at surviving a bite, making it possible for them to flee the fight. Old, seasoned wyverns can often even stomach the venom well enough to push onward after a bite and take revenge for the injury. Inexperienced Trezkul are often taken off-guard by this and meet and untimely end.
Forest wyverns are very territorial. Their females claim a large piece of forest or plains for themselves and stick to it their entire life as long as food and opportunities to gain a mate are present. Should the territory become too dangerous, be it because Trezlin colonists or a stronger predator claim it, then the female would rather try and fight the invaders than simply abandon their homeland. This has made wyverns a pain for newly founded villages, sometimes even their downfall. Their strong bite pierces any kind of armor with ease, making it hard for common people to protect themselves from this creature. One of the best ways to get rid of them is by grievously wounding their body, but leaving their wings intact. If possible, a wounded wyvern will take flight. Should the wings be in tatters, however, the wyvern will fight until death. Usually this means it will take its hunters with itself.
It is hard to scare them off otherwise, as they are by no means stupid. While they are not sapient, they are certainly sentient and will not be impressed by smaller creatures easily. Speech is outside of their grasp. No wyvern is capable of speaking or understanding a language. They could likely be made to understand simple commands, if more by the sound of the words than by actually understanding the words, similar to a dog. They are aware of threats like bows and spears, and will do their best to avoid openly confronting armed groups. They have a preference for ambushes, which despite their big stature are entirely possible, thanks to their fitting coloration. Many hunting parties have been utterly wiped out within seconds after a pair of wyverns pounced them out of hiding.
Wyverns do not live in large groups. They stick with their mate and protect their shared territory together. Other wyverns are seen as a threat, because they will just hurt the quality of the hunting grounds by over-hunting it. Thus rivaling wyvern pairs fight each other. In such clashes, the wyvern pair that is at home in the region will fight fiercely to defend their already acquired land, but the one that is trying to stake a claim on it is likely to retreat. Forest wyverns much prefer to take unclaimed land try and fight another pair of wyverns for theirs.
Mateship is an easy matter among wyverns. It is the females who find and hold a territory, while the males travel around. The female approaches any male that comes into her territory and calls to them, demanding them to land for closer inspection. If the male is interested in pursuing the female, he will land in the nearest free spot and allow the female to approach. Once both landed, the female will move all around the male to see if they are a fitting suitor. Physical strength, health, and age are the most important attributes. Often females will reject young males, forcing them to travel around until they've reached a higher age. After all, an old free male is one that has managed to survive a long time just by traveling around. The older a male gets, the higher the chance a female will pick him. Since the amount of horns is a good indicator for the age of a wyvern, males with an impressive crown are very likely to be chosen.
After the female decided if the male should stay and mate her, the newly founded couple will find a quiet and safe place to build a nest. Be it in the canopies of trees, in a cave, under a cliff or similar. When winter comes, the female gets into heat. She copulates with her mate and remains gravid over the winter, living off of the fat they've acquired over the year and her male's hunts. Now this is where the competence of the male truly shows, as only a capable mate will be able to keep his female well fed through the cold season.
When spring comes around and it is getting a bit warmer, the female lays two to three eggs in their nest. Of course the mother is too large to sit in a tree if the nest is in the canopies, but she can curl around the tree and keep her neck on the eggs. In the other cases mentioned above, she curls up around them to keep them warm, letting her male feed her while protecting the clutch. When spring ends and summer starts, hunting becomes easier and more rewarding. The perfect time for the eggs to hatch.
The first being a freshly hatched wyvern will spot is its mother. Scent and sight will be what identifies her for her hatchlings from then on. They remain with the mother until they are about a season old, then they begin to explore the immediate area of the nest under the watchful eyes of the mother. They play fight, explore, and make some experiences with small animals and insects living around the area. Father will only occasionally be sighted when he delivers food for his family.
Once they are a good bit over a year old, they begin to explore even without their mother watching over them. They hop around near the nest, scare off animals and learn how to stalk around the woods by themselves. After another roughly three years, their wings are finally capable of carrying them into the air and away from their parents. Mother will teach them how to fly proper by having them imitate her own motions. Once they can fly properly, the parents kick them out of the nest. Usually the father chases them off, because he begins to see them as a threat.
Hunting comes naturally to the young wyverns, but sometimes mistakes are made and they go after the wrong kind of prey - like a flock of gryphons or a Trezkul juvenile - and become prey themselves.
The living space of the forest wyverns is, as their name indicates, the forest. It also includes the mountain ranges of the forested north as well as some of the shores. Within Trezlin-populated space they are commonly spotted among the trees and mountains. The trees stand densely, but also make way to the occasional clearing or the fields of the Trezlin. Game can be found where trees makes way for grass, wildflowers or grain. Game that attracts the forest wyverns and makes these places a good territory to claim. Territory has to be defended. Food becomes scarce during the winter and predators are more desperate and vicious, which causes fights for territory to occur more often. Once it gets warmer, prey becomes a common sight and surviving becomes easier.
Forest wyverns only eat meat, but they do not care from which kind of animal. They are as content to feast on a Trezkul as they are to eat large or small game. They only hunt during the night, as that makes it less likely to come across Trezkul. Wyverns only actively hunt defenseless creatures and would only fight a Trezkul for territory or if the Trezkul initiated the fight. Trezlin are usually seen as defenseless creatures, as are their livestock. Forest wyverns do not at all refrain from slaying chickens, cows, pigs, or the farmer's who own them. Even entire villages have been brought to ruin because a pair of hungry wyverns picked off villagers every night, or destroyed the entire village in one fell swoop because they felt they are encroaching on their territory.
Trezkul are the main competitors of wyverns when it comes to food. However, one can not consider the Trezkul a natural predator of these wyverns, as they do not actively hunt them. The two only clash over territory, not out of hunger. The competition has gone so far that the wyverns evolved a natural resistance against the venom of the Trezkul. Gryphons might also be seen as a competitor, as the smart critters can be a serious threat for a wyvern, if they attack as a flock. A singular gryphon easily falls prey to a wyvern.
Of course the main competitors are the Trezlin. It does not matter if it is the Gren, the Sokans or the free people of Treztown - all three hunt the wyverns as they are seen as an annoying pest that steals cattle and makes the lands outside of a village's borders, or even the village itself, unsafe. Many beastslayers of the Gren have earned a fortune by slaying wyverns, because lords tend to pay well to be rid of these monsters. Yet not every beastslayer survives the clash with a wyvern.