Damas, by virtue of being Connacht's lieutenant in life, was certainly equally devoted in unlife. Considering the characteristics of the other Fallen Lords, especially the Deceiver, it stands to reason that one of Connacht's "friends" would be his most trusted servant as the Leveller. Balor need not have sent Soulblighter after the Tain with purposes regarding the Myrkridia; by that time, all the Myrkridia within the Tain were dead. And whether it was Balor's orders or Soulblighter's planning that found the Tain, it was used effectively nevertheless.
Soulblighter's forays into the Untamed Lands were probably well justified. Not only was he fulfilling his personal interests in immortality and the like, but at the time it didn't look like having another Fallen Lord stomping around the West would be all that necessary. The Myth world most likely had plenty of people to subjugate that weren't shown on the map.
Also consider how Soulblighter was at the Great Devoid, attempting to retrieve Balor's head. I imagine this implied that he was either greatly devoted to his master and was attempting to save him, or knew that Balor was relatively powerless in his state, and perhaps that would leave Soulblighter the opportunity to lead the Dark. I have to wonder if he was being honest when he said "Give me the head and I will let you live". I doubt it, just seems funny that he'd offer.
-Lucan
