From The Regnum Animale by Bishop Vitellus of Oaken:
The name of the Invae is one spoken in dread in these dire days. These strange and unfathomable creatures are covered in chitin, hard shells that make them formidable foes. And foes they have made themselves, for they count no other Fauna as friend or ally. Everywhere they have set their feet they have tried to conquer. They see the world through multifaceted eyes, and they fight with many arms. Some may fly as the Avians do, some may burrow as Mammalia, and others may possess abilities yet to be witnessed. Most of the Church's accounts of the Invae come from the reports of crusading knights and Avian refugees, and what they have said suggests that there are varieties of Invae beyond count. We may thank the Flame that the implacable Invae dwell far across the sea to the west, beyond the Avian lands, but we must remember that reports of their hive-ships landing upon our shores are not unheard-of.