So as someone who played all the previous games I wanted to shed some light here...hopefully. I watched the ending, but haven't completed the game yet so I don't know everything about the Arcania specific story line (and yeah, I don't mind being spoilered at all)
Spoiler:The 3 guys are Thorus, an important character throughout the whole game while the other 2 are never named and I don't think I know them so they're probably Arcania characters.
It is important to know that Rhobart III is actually the old nameless hero from the first 3 games. I don't know which of the 3 endings of Gothic 3 Spellbound used as base for Arcania. Probably the Innos one as explained in a second. The story of Gothic was always a bit vague and confusing but it was hinted, that the nameless hero (aka Rhobart III) is the avatar of Innos, so maybe that 'demon' that possessed him was actually Innos or his Spirit, because Arcania strengthens the whole theme of Innos not being the good guy (at least at the start it is mentioned) which was already hinted at in Gothic III.
Another interesting fact that I noticed is, that the plate (amulet?) that the woman has at the start seems to sport the symbol of beliar or even the sleeper (arch demon/end boss from the first game, was probably avatar of beliar).
The game or its story is very much about the gods, their war and everything. The first 3 games we played the Avatar of Innos (God of Sun, Light, Order) because of the hints at the end of Feshyr starting isle, I assume that the new hero is either Avatar of Adanos (to bring overall balance) or Beliar (God of Destruction, Chaos, Absolute Freedom - yeah that is the same as Chaos )
Maybe I get more answers if I continue playing the game. If not, at least the story is still as we're used to it from Gothic
[Edited by StrangeFabs, 10/21/2010 7:48:43 AM]