Ikki Tenryou is the main protagonist of the Medabots series, a young boy whose life changes dramatically when he finally obtains his own Medabot. In the beginning, Ikki is an enthusiastic fan of Medabots and Robattles, but he cannot afford a Medabot of his own, unlike many of his peers. He is known to be a lively, easygoing, and good-natured elementary school student, though he can also be slightly timid at times. His financial situation leads him to a chance discovery: finding a rare Medal in a river, which he then uses to purchase an outdated, inexpensive KBT-type Medabot from a local shopkeeper. He names this Medabot Metabee, forming a partnership that defines his journey.

Ikki's core motivation stems from his desire to prove himself as a skilled Medafighter. He tends to challenge powerful opponents to demonstrate that he is the best, and his passion for Robattling is a driving force throughout the story. Despite his knowledge about Medabots, he is portrayed as a poor student, with his focus clearly placed on his activities as a Medafighter rather than his academic studies. He develops a strong bond with Metabee, though it is a relationship built on friction and mutual respect. Metabee has a strong-willed, disobedient, and sarcastic personality, which often leads to arguments with Ikki, particularly when Metabee refuses to follow orders or questions his owner's strategic commands. Over time, however, their partnership grows into a deep and inseparable loyalty, with the two functioning as a formidable team in battle.

Ikki's role in the story is that of a protagonist who matures through his experiences in Robattles. Initially not a particularly experienced Medafighter, he gradually becomes a more strategic and capable combatant, learning to combine his knowledge with improvisation to overcome stronger foes. He takes on the responsibility of defending the traditional, honorable spirit of Robattling against unethical opponents, including the Rubberobo Gang and later the Death Medarot Company, which produces emotionless Medabots programmed to win by any means. In his confrontations with the Death Medarots, his skills are pushed further, leading him to receive a new Medarotch and upgraded parts for Metabee, transforming the Medabot into the more powerful Saikachis model.

In terms of key relationships, Ikki has several significant connections. His partner Metabee is the most important, with their bond being the emotional core of the series. He is also close friends with Arika (known as Erika in some English versions), a strong-minded girl who often bosses him around and works as a reporter for the school newspaper; she is frequently implied to have a crush on him. His primary rival is Koji, a wealthy and snooty ace Medafighter from a private school; the two constantly compete but develop a grudging respect for one another. Ikki is also romantically interested in a girl named Karin. Throughout his adventures, he is supported by various other characters, including the shopkeeper Henry and the mechanic Nae, who provides him with crucial upgrades.

Ikki's development is clearly visible as the series progresses. He starts as a boy without a Medabot who must rely on chance and resourcefulness to enter the world of Robattling. Through his trials and battles, he becomes a more confident, mature, and strategic Medafighter. His relationship with Metabee evolves from one of conflict and disobedience to a powerful partnership built on trust and mutual growth. By the time he faces major threats like the Death Medarot Company, he has fully embraced his role as a defender of fair competition, showing resilience and a strong sense of justice. His notable abilities lie not in any physical prowess, but in his strategic mind, his ability to improvise during Robattles, and his unwavering determination to protect his friends and his partner Medabot.