This fight is notorious for a couple of reasons.
I'd say this is more a level 13 encounter, than 12.
The problem with Bless is that it is very easy to be undone when you're fighting Voidwoken enemies, or many mid/high level enemies. In many cases, Voidwokens don't have to do anything to create cursed surfaces, while you have to spend 1AP + 1SP. Sometimes just striking them will create cursed surfaces. Tbh, in many encounters I never quite figured out where all the cursed surfaces even came from.
All this means when you do use Bless, your blessed surfaces rarely last for long enough to matter. I suppose with careful positioning and manipulation of enemy positions, you can make it work to a decent extent in certain situations. In this particular encounter to save Gwydian, it's not so easy. I'm not saying it doesn't work at all, just that it requires a lot of effort, the right setup, and possibly metaknowledge, and to me it has never been worth it.
You probably already know, but blessing a cursed surface doesn't turn it into a blessed surface right away. It turns it into the normal surface first. You have to Bless it one more time to make it a blessed surface. So there's that. This compounds the underwhelming performance of Bless. Again, in the majority of cases, enemies can create cursed surfaces - *snap finger* - just like that.
The bottom line is, Bless is pretty much useless in any fight that can be considered tough. Especially when compared against many other skills you have access to, at any given level. If you're not getting it to work very well, you might as well change your tactics entirely. Trying too hard to make it work probably just makes the whole thing harder for you.
As for the encounter itself. Having a dedicated hydro/healer character in the party goes a very long way, since the healing, the magic armor restoration, and the water damage work greatly in this fight. Stock up on scrolls of Armor of Frost and Restoration and distribute them to all party members.
Dome of Protection also works very well since your party will be clumping up together on the top platform for most of the time.
Potions help a lot too. If you don't mind some crafting and hunting for ingredients, you could make a bunch of Large Potions of Fire Resistance and give them to everyone.
Here's a little personal trick I learned on my current playthrough: notice the tents near the beach. If you have Teleportation and are standing on the top platform, you can teleport the big blobs to where the tents are. They will be stuck there and do nothing. There is also a rock in the vicinity that you can teleport enemies on, and they will also be stuck there. They could definitely jump off, but they didn't do that in my game. Probably because it was too far from the scaffold. I'd guess that enemy AI doesn't work as effectively when they're too far away from the scaffold and everyone else.
Another trick someone has also mentioned, is that having everyone run to the beach and make your stand there makes it much easier, because NO ONE CAN CURSE THE OCEAN. Or to be more precise, no one can create cursed surfaces on the sea.
Last edited by Try2Handing; 02/10/18 03:28 PM.