I'm just now getting back into games after a long hiatus (my last major 4x game was MOO 2!!), so I am waaay out of the loop on games in general.
/old man preamble. 
Okay -- I'm confused about the Ultimate Edition. When I play, it defaults to 'Twilight Of The Arnor v. 2.20'. Is that basically the same thing as Dread Lords and Dark Avatar - just with additional features and content? Or are they three separate games within the same universe (like how Star Trek 1, 2 and 3 are different movies but the same franchise).
I guess if it's a single game that has been expanded upon, the user manuals and explanations I seek ought to be the ones for 'Twilight Of The Arnor', right? Since the information there will be most current and I'll be able to do things that wouldn't have been possible in Dread Lords or Dark Avatar. Or am I just totally misunderstanding all of this?
Sorry for the confusion. Space 4x games have apparently changed a lot since I last played them...