Well, I just finished the game tonight. It is a good story, if a bit daft. Evil people destroying everything living. Trite story that really never has made any sense. If everything is dead then what do they plan to lord over? Especially since they are invincible and immortal. Living forever and being unable to destroy anything because they already destroyed it all. What an incomprehensible amount of boredom they have in store for themselves. Brilliant... Ok... Daft.
I don't think they have any domination purpose, I would bet more about rage and revenge feeling. Ygerna showed to Damian his evil side because the Divine One killed her father; Damian decides to destroy Rivellon because his father killed his lover. In
Child of Chaos, Damian told Lucian, 'When you killed Ygerna, you took away my right to choose. And now there is no choice to be made anymore!' That's the point I think; the death his father isn't enought to make him pay for that murder, he wants to prove his father was deadly wrong. He wants to destroy everything the Divine One tried to save.
In that point of view, their evil love is leading to the destruction. I don't think that's going to separate them.
