I actually finished the Dominion thread! *cries and blows nose noisily*
The next lost discipline would be Unity - which I have actually planned in my head and have toyed with since that old quest of mine, The Game - but that one's more heretical than Dominion. What if you could take a (willing) group and turn it into a single entity, forming a soul-sharing gestalt? And when someone cuts you, a Master Unifier, down, you can just transfer the wound to someone in your group, killing them instead?
Anyway, my next priority is finishing the Ravarisk quest.