I think it probably doesn't help to dwell too much on the motivations of 'dark lords'. In the case of Sauron, I know he was one of Morgoth's lieutenants, but what does he really want and why? What's his ultimate goal? To have power, yes, but to do what with it? So he can sit on a big throne on his own in the dark for thousands of years, while ostensibly being 'in charge'? It doesn't really stack up the more you think about it... so it's maybe best not to think about it too much! While reading LoTR I would occasionally wonder what the Nazgul did in their various towers and fortresses as the ages pass. Did they play chess with each other? Compose poetry? Did they look longingly out the window at the world around them, with wistful longing? At least orcs get to run around, breathe some fresh air, hunt, mate and have lives that had meaning for them. The big bosses of epic fantasy apparently live solitary existences in dark towers of stone, just sitting there, brooding for eons... seems kinda rubbish. If I was Sauron and I managed to 'endure' after I lost my ring in the second age, I'd go and live in Bree looking like a regular bloke (I can choose how I look), drink mead, enjoy the odd pie and mash, and enjoy my immortal existence. You're just cutting your nose to spite your face sitting in that tower, Sauron. I guess I'd make a poor dark lord.