Eraqus will likely take a stand and assist at the portal, in order to prevent the Darkness critters from crossing over into this makeshift nexus of realities. He'll do what he can to ensure those he's familiar with are safe - or dealt with, depending.

As for how well that works out for him... Well. Eraqus will likely end up crossing through one of those portals once the Core Nexus closes, though where he may end up next is uncertain.