Olympus and Asgard are going to war. I dunno why... it may have something to do with ice cream.
Anyway, Thor and Heracles square off against each other.
Thor is armed with Mjolnir, his iron gauntlets, and his belt of strength. Heracles has the Nemian lionskin as armor, a massive wooden club (Olympian wood so a lot more durable than mortal wood), and bow and arrows dipped in Hydra venom.
This is Heracles after ascending to Olympus. His feats of strength include slaying lots of giants in the Gigantomachy, wrestling Zeus to a standstill, taking the weight of the sky from Atlas, and defeating Thanatos (death) in a wrestling match.
Thor's feats include slaying lots of giants, catching Jormungandr (the Midgard Serpent which encircles the earth) and drawing him up on a fishing line), and wrestling Elli to a standstill.