If I remeber right, I have more than 1 dragonskillbook found before that point in the game! But I going to the Battle Tower (first time I played D II) when I was level 21! And I had that time already killing all enemies in the Mine behind the waterfall in the Orobas Fjords + also that other Mine (swimming to that place!).
Second time I wish to have my Battle Tower earlier!
To be honest, I enjoying Divinity II still, after all I know about the ending!
I don't know exactely what it is, but this game will keep my thoughts down

Maybe the female character/hero gives me more satisfaction?
I find the woman looks nice, walk more funky, swim attractive and take an elegant move after reaching the top of a ladder!!
