The kalyuga is a flying species native to Vertan. Kalyugas are shrew-like creatures borne aloft upon wings akin to those of a bat, with nut-brown fur shot through with thin black stripes. The creature's face, topped by two beady black eyes, terminates in a rounded snout. Its teeth are composed chiefly of curved fangs, suggesting a carnivorous diet. Typical kalyugas are known to grow to about the size of an eagle.
Behaviourally, the species is known for unprovoked aggression; shrill, high-pitched screaming is not uncommon, though its primary means of attack on larger beings seems to be that of an aerial battering motion. The kalyuga is noticeable as the only Vertani animal species to not have been adapted for domesticated use in the village of Tir Murann. Whether this is due to its aggression or simple administrative oversight remains unknown.
Kalyugas have only been seen upon Sapience during the Vertani War, when the Vertani monuments were activated.