Board Thread:Questions and Answers/@comment-4539970-20130506113812/@comment-4384097-20130511070534

Battle 1: Water Hazard, as he would drown Heatblast while resisting the flames.

Battle 2: Big Chill, as Diamondhead's shards wouldn't be able to touch him, allowing him to freeze the latter.

Battle 3: Big Chill, as he isn't composed of metal and would easily freeze Lodestar.