Adra Dragon for sure for me. At the very least Adra Dragon at level 12 in original game was much harder than any of the others at level 13+. Have never fought Adra Dragon at level 16 so its possible its quite easy if you do.
Beat all the WM bosses (Llengrath, Alpine, Concelhaut, Radiant Spore, and Kraken) on the first try on PotD, while Adra Dragon killed me 2-3 times on hard first time I played the game.
I think the Adra Dragon to me was more difficult because its alpha strike (the breath it opens combat with) is so strong, so unless you send in a lone tank to eat it you're just rolling the dice and hoping your whole party doesn't get screwed. The others give you time to act letting you cast buffs and CC/debuffs. Llengrath especially would probably be really hard if it wasn't for the fact that her gang starts all the way over there, so when they actually come you're already Alacritied, Crowned for the Faithful, and standing in a Moonwell.
Edited by limaxophobiacq, 22 March 2016 - 03:04 AM.