Many people have finished Divinity 2. So the final battle is certainly not impossible.
Change your tactics, maybe?
Of course it can be finished, assuming your character is at the necessary level and you have spent skill points in a certain way. But I look elsewhere on these forums and see others are in the same boat, simply because they took their character in a direction that makes the final battle impossible to complete.
I find the idea of "tactics" in Divinity II to be amusing, since most boss tactics involve rolling, jumping, and exploiting the bad pathfinding and AI rather than actual tactics as you would find them in other, better RPGs. There is no "tactic" in this battle. With my summoned demon and my creature, I cannot damage either character faster than they self-heal. I can wail on them for hours, even after consuming the best potions in my inventory, but not defeat them--even though the hours of cakewalk that preceded it communicated to me that I should have been more than ready.
This isn't difficulty--this is imbalance, a quality that intrudes on a fair bit of the game. It's why so many complain of the difficulty. If you are going to make a hard game, you need to give the players a tight and precise combat system. This is what separates hard games, like Demon's Souls, from cheap and unbalanced games, like Divinity II. I like a good, tough-as-nails challenge. But Divinity II does not offer precision of attack nor precision of movement. You win by exploit, not by tactic. And that is a serious flaw.
I was able to win, finally, by dragging my difficulty slider to easy, though after viewing the ending, I wondered why I put in all that effort to finish that battle. Goodness gracious, what a poor ending.
