Thor #238 (1975) First Print

With Jane Foster as his hostage, Ulik is able to 'compel' Thor to come help him seek revenge on the Troll King. Ulik needs Thor to battle Zotarr -- the Troll Supreme, who guards the king. As they travel along an underground river, they are attacked by a Sea Demon, which Thor easily dispatches. But on the shore awaits the Troll King and Zotarr.  When Ulik is taken out of the battle, Thor uses his hammer to knock his adversary to his knees. He then delivers a devastating bare fisted hit to Zotarr's face. His fallen enemy's shattered helmet exposes his robotic face. During the battle, Jane Foster has freed herself from her captors and single-handedly captures the Troll King. A side story, has Odin (under his self-imposed amnesia) using his awesome strength to quell a fight between picketing workers and the ruffians hired to beat them up.