Gao Mikado serves as the central protagonist across multiple Future Card Buddyfight series. Born into a family operating a Mikado-style Aiki-jujutsu dojo, childhood martial arts experiences forged an early obsession with winning that accidentally harmed others, creating lasting guilt and shaping his future approach to conflict resolution.

His journey ignited upon obtaining a Buddy Rare card and meeting his first buddy monster, Drum Bunker Dragon. This partnership defined early strategies centered on Dragon World mechanics, specifically Armordragons. A driving philosophy emerged from strong identification with the "Mighty Sun Fighter" persona—a heroic concept created by his deceased older brother, Yota Mikado—emphasizing protecting the vulnerable and using Buddyfight battles to forge friendships, even with former adversaries like Kyoya Gaen.

Leading Team Balle du Soleil in the ABC Cup demonstrated growing skills alongside recurring challenges; victories sometimes inadvertently caused allies like Drum or Kiri Hyoryu to doubt their abilities, leading to temporary separations. During this period, he wore the core deck case as a belt buckle, utilizing a flying platform Buddy Skill. Deck-building evolved significantly after Drum departed for training, prompting experimentation with Magic World and Dungeon World decks to accommodate Drum's Dragowizard and Brave forms upon return, alongside a Dragon World deck incorporating Thunder Knights.

Later story arcs introduced new buddy monsters and specialized decks. After Drum permanently returned to Dragon World to lead his clan, partnership formed with the newly hatched Dragon of the Sun, Bal Dragon. This era utilized the Sun Dragon archetype and Impact Monsters for global competition in the World Buddy Cup. Selection as Dragon World's representative for the World Buddy Masters tournament led to bonding with Demon Lord Dragon Batzz. This partnership employed a Thunder Empire deck centered on the Overturn mechanic, facilitated by the Thunder Emperor's Fangs flag. A unique fusion ability, "Protection of Batzz, Dragonificator Gao," combined their physical forms and powers during battle. These later decks embraced greater strategic risk, often requiring low life points or damage reception to activate key effects.

Significant power manifestations include Future Force—a golden aura state causing hair elongation and floating—and multiple Dragon Force forms. The "Style of Impact" Dragon Force utilized fire-based punches, while the Dragon Force of Anger featured fiery wings flaring to life under intense emotion. Later impacts carried risks of physical strain, including temporary separation from the body.

Key relationships feature a friendly rivalry with Tasuku Ryuenji, eventual marriage to Paruko Nanana, and fatherhood of two sons, Yuga and Haru Mikado. A defining moment occurred when moving to America precipitated the GGG Cup tournament in his honor, featuring major rivals and all three buddy monsters. This relocation concluded his active role in subsequent series, transitioning him into a referenced but unseen figure.

His personality blends unwavering optimism, protectiveness, and a strong belief in friendship's power with a deeply buried violent temper. This temper surfaces rarely, triggered by threats to friends or family, often leading to aggressive or reckless actions. Trust is granted easily, sometimes resulting in vulnerability. Significant development followed a canonical loss to Ikazuchi, shattering an extensive winning streak and prompting introspection about heroism. His appearance includes short, spiky black hair with red accents, golden eyes, and a signature reversible jacket bearing sun motifs, typically paired with indigo sweatpants.