If you have a saved game prior to entering Hall of Echoes reload it. Make sure you are lvl 34 at least.
If you are already lvl 34 then take the difficulty slider and put it on Low difficulty.
Immediately after the auto save after the cutscene jump, jump jump, around the columns until you get the AI of the enemies hung up on the throne or one of the columns to separate them. Pause, drink resist potion. Pause drink Str potion. Pause drink Int potion. Try to get the divine on his own and trounce him. Or get the divine away from the others and kill the followers first. Divine has a way of rush attacking you though so you may need to kill him first.
JUMP ATTACK him.
Pause and drink health potions even when you don't need them.
These guys at Larian just really must have had a hard time figuring out how to make a cool boss battle so they just made this one really cheap so players couldn't just wipe the floor with everyone at end game.
They need to play some games that have cool boss battle that actaully take TACTICS to beat and that are fun. This game doesn't have a clue on how to make the battles against the important villains stand out.