Pretty new to this. I see FFG have a Runewars game (well 2, 1 is a world based building game and 1 is a miniature battle game??)

Am I right in saying Descent is set in that world also? Is there anywhere I can have a read about that world or where descent fits in? Cheers.

Yes you are correct.

Heroes, units and lore are all common between Descent/Battlelore/Runebound/Runewars.

Well if u go to FFG products u will see that they are all set in the Runebound section.
(the realm of Terrinoth)

An with the release of the new Runewars-Miniatures game, they are pushing the lore a bit. Up until now, is was rather rudimentary.