Mikey Kudō is the main protagonist of Digimon Fusion, a cheerful and compassionate middle school boy who becomes the leader of the Fusion Fighters in the Digital World. He is a thirteen-year-old seventh grader with a pair of red goggles worn on his forehead, a signature trait of Digimon series protagonists. He lives with his mother while his father works as a sports trainer traveling around Japan.

Mikey’s defining personality trait is his unwavering drive to help anyone in need, encapsulated by his catchphrase “I can’t ignore this.” This attitude stems from a past event where a classmate told him not to worry and later ended up hospitalized; after that experience, Mikey vowed never to turn away from someone who appears to be struggling. He is naturally optimistic, warm-hearted, and approachable, which makes him easily liked by both humans and Digimon. He possesses sharp observational skills, quick thinking, and strong athletic ability, excelling in a wide variety of sports without specialized training. However, his tendency to overexert himself in helping others sometimes causes him to collapse from exhaustion.

His motivation throughout the story is to protect the weak and bring peace to the Digital World. After hearing a mysterious melody and the cry of a dying Digimon named Shoutmon, Mikey receives a red Fusion Loader from the legendary Digimon Omnimon. This device allows him to combine Digimon through a process known as DigiXros, creating powerful fused forms. Using his Fusion Loader, he becomes the General of the Xros Heart army, later known in the English version as the Fusion Fighters.

His role in the story is central across all three arcs of Digimon Fusion. In the first arc, he travels through various zones of the Digital World to collect Code Crown fragments and oppose the Bagra Army led by Lord Bagramon. In the second arc, he works alongside rival Generals Christopher Aonuma and Nene Amano to defeat the seven Dark Generals who rule the kingdoms, ultimately saving the Digital World. In the third arc, set a year later, Mikey is now in eighth grade and takes on a more supporting role, forming a street basketball team called Xros Heart and acting as a mentor to younger characters, especially Tagiru Akashi. He passes his own goggles to Tagiru at a critical moment, symbolizing the transfer of the heroic spirit.

Key relationships shape his journey. Shoutmon is his closest partner and friend, a Digimon who starts as a small, loud creature but eventually becomes a leader in his own right. Angie Hinomoto and Jeremy Tsurugi are his childhood friends from the human world who join him in his adventures. Nene Amano becomes a trusted ally and later a friend, and her younger brother Ewan Amano is rescued from the influence of the Bagra Army. Christopher Aonuma initially acts as a rival but later becomes a comrade. Tagiru Akashi looks up to Mikey as a role model, and Mikey guides him patiently while allowing him to grow independently.

Over the course of the series, Mikey develops from a well-meaning boy who simply wants to help into a seasoned General capable of uniting diverse Digimon and human allies. He learns to balance his selfless nature with the responsibilities of leadership. His notable abilities include strategic command on the battlefield, the power to initiate DigiXros to combine multiple Digimon into stronger forms, and the ability to hear the DigiMelodies of dying Digimon, which allows him to sense when a Digimon is in desperate need. He also demonstrates remarkable combat instincts despite being an ordinary human, often outsmarting opponents through logic and teamwork.