Can't seem to get past bulwark boss

[difengamer]

Hello.

My first post. If it does belong to different board, please let me know.

I have a problem with my first playthrough. I got my dwarf bulwark to level 50 (normal/adventure). So far had no problems with any fights. Sure, sometimes it took a while to whittle down some bosses, but eventually they all died. All except bulwark orc. I'm sure I'm doing something wrong or I don't know something obvious but we just can't seem to kill each other. We keep blocking and counterstriking like crazy, regenerating HP and the circle never ends. I got him down to 56%, but in a few turns he got back to like 90 and then the story repeats. Is there a trick to this fight?

I definitely did not optimize my talents and gear, as I'm playing for the first time but I think I got at least some stuff right, considering I'm still alive and cleared almost all zones/quests in the vanilla game.

Any help or tips are appreciated.