Geki is the Tyranno Ranger and the leader of the Zyurangers. Raised as the prince of the Yamato Kingdom, he grew up believing he was the son of the king and queen. In truth, he was the younger son of the Black Knight, and his adoption into the royal family became the source of Burai's hatred and the tragedy that shaped both brothers' lives.

As leader, Geki is loyal, courageous, and fiercely protective of his teammates. He helps guide the Zyurangers as they awaken their Legendary Weapons, restore their connection to the Guardian Beasts, and fight Bandora's schemes in the modern world. He transforms with the Dino Buckler, fights with the Ryuugekiken, and commands the Guardian Beast Tyrannosaurus.

Geki is deeply shaken when Burai returns as Dragon Ranger and attacks the team. Even after learning that Burai is his older brother and that Burai has sworn revenge against the Yamato royal family, Geki refuses to give up on him. His compassion eventually breaks through Burai's hatred, allowing the brothers to reconcile and giving the Zyurangers the chance to fight together with Dragon Caesar.

After Burai's final death, Geki inherits the Dragon Shield and the Zyusouken. With these, he becomes Armed Tyranno Ranger and gains the ability to call upon Dragon Caesar. This form carries Burai's legacy forward, turning the power once used against the Zyurangers into a symbol of Geki's bond with his brother.

After Burai dies, Geki receives the Dragon Shield and the Zyusouken. These allow him to fight as Armed Tyranno Ranger and to summon Dragon Caesar when the Zyurangers need Burai's power to continue protecting the Earth.