Do you have the patch installed? See the appropriate support page for
DKS or
FoV.
There was a bug where boss type opponents could have over-powered attacks. The patch will prevent this problem, but unfortunately if it has already occurred in the save it will not undo it. However, if you email your save to support@larian.com, with a description of the problem, they can fix it for you.
If you can not use the quest item shield, do you have a skill point you can put into the Hide in Shadows skill? As mentioned above, your creature and possibly a summon might take care of them. A Stun Arrow, or possibly a Rush Attack, or something, may let you finish either off before they can hit you, though if they both have over-powered attacks it may be tricky taking out both of them without getting hit.
One person, with the PC version of the game, who ran into this problem used CheatEngine to fix their health until they got past Ba'al (someone mentioned that Steam may have a problem with the use of CheatEngine, though, even with a single player game).
Where's the trick to Ba'al?[Not Sure if Bug][Spoilers]Killed InstantlySee Lar's post
here on how to send them an Xbox save.
With the PC version, in XP the saves are in the folder
C:\Documents and Settings\ %username% \Local Settings\Application Data\Divinity 2\Savegames
or in Vista / Win 7
C:\Users\ %username% \AppData\Local\Divinity 2\Savegames
You may need to set Windows Explorer to show hidden files and folders (
XP, Vista,
Win 7).