Ikki Tenryou is a young, energetic boy who serves as the main human protagonist. He is characterized as lively and easygoing, though he can also be a bit timid at the start of his journey. His greatest dream is to own his own Medabot and become a skilled Medafighter, but he comes from a background where he cannot afford one. His life changes when he happens to find a rare Medal in a river, which he uses to purchase an outdated, inexpensive Medabot model that he names Metabee. This discovery sets the course for his adventures.

A significant aspect of Ikki's character is his relationship with Metabee. Unlike the typical harmonious partnership between a Medafighter and their robot, Ikki’s Medal appears to be defective, as Metabee is incredibly stubborn, aggressive, and often refuses to follow Ikki’s commands. Their partnership is initially fraught with conflict and comic arguments, but through numerous Robattles and shared challenges, a deep and trusting bond grows between them. Ikki learns to trust Metabee’s instincts just as Metabee learns to respect Ikki as his partner.

Within the story, Ikki is not initially a full-fledged or top-ranked Medafighter, but he gradually matures through the battles and rivals he encounters. He enters the World Robattle Championship and, with Metabee, faces a variety of threats. These range from the petty medal thieves of the RoboRobo Gang to more serious villains like the Phantom Renegade. He also becomes the apprentice of the great Dr. Medarot after it is discovered that Metabee possesses the rare ability to use a powerful technique known as the Medaforce. As the series progresses, particularly in the sequel Medarot Damashii, Ikki faces the Death Medarot Company, which produces unethical robots called Kilobots. In this conflict, he takes on the role of defending the traditional, honorable spirit of Robattling, receiving upgrades for Metabee to combat this new threat.

Ikki's key relationships help define his growth. He is supported by his childhood friend, Arika, and her Medabot, Brass. He develops a friendly rivalry with the serious and arrogant Koji Karakuchi, which pushes both of them to improve. He also meets Hikaru Agata, a store clerk who is secretly the Phantom Renegade and was Metabee’s original owner. His personality is consistently defined by his determination, his loyalty to his friends, and his unwavering sense of fair play. While his strategic commands are sometimes questioned by Metabee, his ability to improvise and his deep understanding of his partner's capabilities make him a formidable Medafighter. A key part of his journey is learning to harness the Medaforce, a mysterious and powerful energy that dwells within Metabee's rare Medal, which they learn to activate together in critical battles.