Rungo Iron is an American miner defined by physical strength and a kind heart. The kidnapping of his wife Lila and son Christopher by the Secret Society propels him into the Battle Arena Toshinden tournament, driven by the desperate need to rescue them.

After the first tournament, Rungo wrestles with betrayal over Gaia's scheme: the orchestrated uranium deposit discovery that nearly cost him his job. This deception aimed to lure him into the competition rather than seek his direct aid. Though betrayed, Rungo remains conflicted, sensing Gaia's actions might have harbored deeper motives tied to the tournament's underlying conflicts.

When invited to the next tournament, escalating threats against his family force his return. He reenters the battles determined to confront Gaia directly, demanding answers about the tournament's true purpose and the ongoing danger to his loved ones.

Rungo fights primarily with a pickaxe, an extension of his mining expertise and practical approach to combat.