The theme appears to revolve around a league of humans and their dragons fighting trolls (or some such enemy) who themselves own other dragons. The concept is intriguing, and the sets are very well designed.
Here's a look at each set:
64011 Issiad Battle Pack
64012 Myrdoc Battle Pack
64013 Desert Duel
64014 Necromancer's Peak
64015 Fythold Ultimate Dragon
64016 Ormser Ambush
64017 Skolek Confrontation
I suggest you check out many more pictures of the sets, as well as in-depth descriptions, in the Dragon Lands Flickr album.
Any other custom themes you think I should cover on Brickology? Please do not hesitate to let me know in the comments or through "Contact" above!
UPDATE (8/9/14)- here's the just-posted set 64018 Alchemist Workshop:
UPDATE (8/13/14)- just in, here's another set, 64019 Siege of Issiad:
UPDATE (9/21/14): Wave 2 of Dragon Lands has been revealed (or is being revealed)! Instead of updating this post everytime a new one is uploaded, I'll just provide you with this link to Nuju Metru's Dragon Lands Flickr Album so you can see all the new sets. Which you really should.