2 of us shared this adventure; exactly as the devs designed it to be played.
I did 1st half of the island, my guildie did the 2nd half.
The "Complete adventure" banner won't pop up and the palace is still there even tho no enemies in it. Nothing showing as "attackable" or even registering as can be attacked either. so cant even send 1R to empty camp.
http://prntscr.com/a3932w