"Medarot Damashii" is the second anime adaptation of the "Medarot" franchise, serving as a sequel to the original "Medarot" series. The story centers around Ikki Tenryou, a young boy who becomes the owner of a Medarot named Metabee, a robotic companion powered by a rare Medaforce ability. Medarots are small, customizable robots used for battles, and their Medals, which serve as their cores, determine their personalities and abilities. The narrative explores Ikki's journey as he navigates the world of Medarot battles, friendships, and rivalries.

The series begins with Ikki and Metabee participating in the World Robattle Cup, a prestigious tournament where Medarot users from around the globe compete. Alongside his friends, including the skilled Erika and her Medarot Brass, Ikki faces formidable opponents, including the mysterious and powerful Phantom Renegade, who seeks to disrupt the tournament for unknown reasons. As the competition progresses, Ikki uncovers deeper secrets about the Medaforce and its connection to the Medarots, leading to high-stakes battles and personal growth.

A key subplot involves the rivalry between Ikki and his classmate, Kouji, who pilots the Medarot Rokusho. Their dynamic evolves from antagonistic to cooperative as they confront greater threats together. The series also delves into the ethical implications of Medarot technology, particularly through the actions of the KBT Corporation, which seeks to exploit the Medaforce for profit and control. This corporate intrigue adds a layer of tension to the story, as Ikki and his friends must protect the Medaforce from falling into the wrong hands.

The narrative balances episodic battles with an overarching plot, gradually revealing the true nature of the Medaforce and its potential to bring harmony or destruction. Themes of teamwork, perseverance, and the bond between humans and their Medarots are central to the story. The series concludes with a climactic showdown that tests Ikki's resolve and the strength of his relationships, ultimately emphasizing the importance of trust and unity in overcoming adversity.