Ryo Sanada is the first Ronin Warrior to appear on the scene just minutes before the Dynasty strikes. He is known as the unofficial leader of the Ronin Warriors, often leaping into battle with or without his friends. He is seen as the most emotionally driven Ronin Warrior who will do anything to protect his friends, even at the cost of his own life. This sometimes infuriates the other Ronin Warriors, who hate that Ryo tries to take on everything by himself when he can depend upon them. Truth of the matter is, Ryo doesn't want to see his friends hurt. He is passionate, compassionate, loyal to a default. His temper and his habit of self-blaming when his friends get hurt or when things don't go right are weaknesses he has to learn to overcome. Other than Talpa and the Dynasty, Ryo's own worse enemy can be thought of as himself. Ryo bears the Wildfire armor and is the sole wearer of the Inferno Armor. The Inferno armor can only be called when the other four Ronin Warriors send their power over to Ryo. Without them, the Inferno armor is useless. His Wildfire swords are two katanas and he wields the Soul Swords of Fervor of the Inferno Armor. His attack powers are "Flare Up Now!" which sends a devastating explosion of an extremely intense heated white flare, and "Rage of Inferno", a cyclone of fires that destroys anything in its path. His virtue is "Virtue."

Ryo's family actually descended from a very famous ninja clan on his father's side, but Ryo knows little about them having never met his father's family. His mother died when he was very small, and he doesn't remember anything about her. His father, (name unknown) raised Ryo by himself, but for the most part left Ryo alone with his own bank account for anything he needed while he went away on wildlife photography trips. As they live so far from civilization, Ryo has to walk nine miles to reach school.

It was White Blaze who found Ryo. First when he was a small boy at age four, then when he got a little older at seven, and finally at the age of ten. It was at this age that White Blaze led Ryo to the Ancient One for his immediate training in the war against Talpa.

Ryo gained his armor through his compassion of two poachers who set fire to the woods, hoping to lure some animals out. In an effort to save them, despite their threats to shoot him for interferring in the first place, and the animals, the kanji "Jin" appeared on his forehead and the Wildfire armor formed around him, becoming an official Ronin Warrior. Later on, during a furious battle against Talpa, Ryo would acquire the mysterious Inferno Armor, a powerful armor said to be capable of destroying a planet.