Hi there and welcome,
in order to kill the golems for good, you need to burn all of their mana.
You can do so in several ways, for example by having the mana burn combat king on your characters. Some items too burn mana, one of Galeoth's set (can't remember which one exactly) do so on every attack, and I think there should be some items that steal or burn mana on activation available for chapter 8. If i remember correctly even Rikhano'set should do.
After you complete the quest if you have the animal set you can improve it by clicking on the troll leader. The improved version is not bad at all actually.