Ivashu are creatures of Ilvir, known as the Fatherless Multitude by the faithful, or the Accursed Beasts of the Barren Circle by non-believers. Ilvir creates the Ivashu at Araka-Kalai, making use of a limited number of souls over and over again. Some Ivashu are fairly common, because they have proved most adaptable to survival, or because they are the easiest to create. However, Ilvir also enjoys experimental lifeforms and can produce any conceivable beast in some quantity. Many varieties are unique, created to perform a specific task, or just to amuse the deity.
GM Note: The existence of Ilvir and the Ivashu provides GMs with a rationale for introducing any type of creature into their campaign. As long as these creatures are Ivashu, unable to reproduce, there will not be a lot of them. Campaigns will remain balanced even if the new creatures turn out to be more deadly than the GM anticipated. The local knight can probably deal with the occasional beastie, otherwise aid will be enlisted from a liegelord, and eventually from the king if necessary. As long as the creature is not strong enough to defeat an entire kingdom, it will be dealt with sooner or later.