Thor Boss Battles. Help Thor battle against the villainous Grandmaster in Thor Boss-Battles. The relics inside odin’s value was stolen by the Grandmaster. Now you must adventure together with Thor as he battle Loki, Enchantress, and Hela in each of the stages. You’ll face many challenges along the way. Use the power of thor’s hammer to smash enemies to pieces. Will you be able to defeat the Grandmaster and receive the lost relic? Enjoy and have fun in playing this free online action adventure game on Round Games.