Based on the best information I have, Perdan doesn't even care about Eponllyn, let alone Caligus. They just want to found a colony, and one of the regions either slated to be in it or on the way flipped from Nivemus to Eponllyn partway through.
Perdan is not interfering in the Shadowdale/Caligus war. Eponllyn is choosing to be distracted by Perdan from aiding Caligus.
