Personally I'd like it either way, but since it has some plot holes I say no.

Edit: Just saw ZD Tenakth at desert capital by herbalist.

Could you post this theory for folks who have never heard of it?

The Tenakth, Ullia, that you fight against to capture the bandit camp, Blackwing Snag, has similar markings to the Tenakth that you see at Sunfall. It states that she's most likely (or is) from the Lowlands clan. I presume that this may also be the case with the Tenakth NPC.