They travelled in mating pairs.
A pair of Agenahls were the first known creatures to infiltrate The Valley through a breach of the mists at Declan Reach as the magic was disappearing. They were the first to kill any humans; the trackers Bayleen and Rausha.
Bearers of the Black Staff
One of them in turn was killed in the swamp by Sider Ament whilst the other, despite heavy injuries, managed to escape and return to the outside world.