Guyferd is the name given to Gou's transformation because it is the name of the state of perfect integration with the Fallah virus, as Gou is.
As Guyferd, Gou sports a red outfit with silver adornments akin to Jet Jaguar and Ultraman. He wears a helmet with three fin-like protrusions and a crystal on the brow. His belt, chest, shoulders, fingers and eyes have a gold color. The sphere on his belt buckle plays a major part later in the series.
Gou Kazama was trained in martial arts, but wasn't motivated to fight because of his pacifist mentality. However, after having his body modified by Crown and realizing that he was the only one who was able to stop the evil organization, he decided to start fighting. At first, he had trouble using his powers, but after meeting a spiritual mentor of the Ken'nou-ryu, he managed to use the power of the five elemental "energies" ( Fire, Water, Earth, Nature and Metal) and the two ethereal energies (Air and Star), and turn those energies and his life force into deadly attacks to defeat his enemies. Besides, as a trained and very talented martial artist, he was already a dangerous match for his opponents. While he is a good-natured man, he was very angered by the misdeeds of Crown. Moreover, he suffered from not being an human being anymore, even if his friend reminded him that the most important thing, his good heart, was still making him being human despite his modified body.
After hearing that his brother Masato Kazama had gone missing, Gou Kazama returns to Japan to look for him. While following a lead from a rival Kennoryu fighter, named Taki, who has set a trap for Gou, and turns him over to Crown, an organization that wanted physically disciplined individuals to convert into Guyborgs. When Gou awakens, he finds himself wearing a Guyborg uniform. Crown's leader, Mr. Bicross, informs Gou that he is now a Guyborg, a soldier to protect the earth. Gou claims that he wants to decide what to do with his life for himself, but he and a platoon of other Guyborgs are sent to capture an escaping test subject named Jerks, who is really Taki after having been exposed to the mysterious Fallah virus. During the mission, Jerks destroys the other Guyborgs while Gou watches from a short distance. He is soon approached by Takeo Shiroishi, who explains Taki's condition. Shiroishi then attacks Shiroishi, and Gou steps in to save him. Because he is fighting to save Shiroishi, Gou awakens the Guyferd state and defeats Jarks. He and Shiroishi then escape Crown together.
Gou awakens after a dream about fighting Jerks, causing him to believe that it had all been a dream, but discovers that it was real when he bends the metal bed frame by touching it. He is then approached by Shiroishi, and the two began to discuss why Gou did not become a Mutian when exposed to Fallah. They conclude that it is because he and the Fallah are in symbiosis, and that the Fallah activates when he focuses his ki to enter the Guyferd state. The two return to Taki's dojo, where they find Rei and Yuu Kujou attempting to find Masato by themselves. They part ways, and Gou saves them from Dogross, who is quickly collected by Crown. While searching for clues about Masato, the Kujous are used as bait for Gou, who refuses to transform into Guyferd while fighting in order to preserve his secret. When Shiroishi gets the Kujous away from the battle, Gou transforms and defeats Dogross, but after learning that anger triggers the Guyferd state, Gou begins to question his humanity.
While following a lead on Masato's whereabouts, Gou encounters Volgis, and cannot transform to defend himself, leading to him being knocked off a dam. He then goes to the mountains to find Jimyo, a warrior priest in the mountains, who teaches him about the seven kis of Wood, Fire, Earth, Metal, Water, Star, and Wind. He begins to train Gou in the kis, and is eventually found by Yuu Kujou, who tells him that Crown is setting bombs on a dam, causing Gou to leave his training to take care of it. When he arrives, he finds that Volgis is holding Rei Kujou captive. Gou fights and defeats Volgis while she and the rest of the group who had rescued her defused the explosives.
The Gaiksou technique allows Gou to transform into Guyferd.
Ultimate Star Fist (Kyouksouken)
Utilizing Star energy, Guyferd can deliver this powerful move as his final attack.
Utilizing Fire energy, Guyferd rapidly punches his opponent before using a smashing blow with his right fist.
Utilizing Earth energy, Guyferd deliver a crushing kick upside the head at blinding speed.
Air Flower Dance
Utilizing Natural energy, Guyferd repeatedly execute a drop kick attack on his opponent.
Utilizing Metal energy, Guyferd uses the air currents to deliver a flying drop kick against his opponents.
Smashing Hit Kick
Utilizing Water energy, Guyferd uses a drop kick to severely wound an opponent.
Thrusting Dragon Attack
Utilizing Aerial energy, Guyferd delivers a destructive ‘cross’ karate chop attack.
Combined Energy Ultimate Star Fist
Used in the final episode of the series. A powerful attack resulting from the combination of Guyferd's and Deathferd's Kyokuseikens.
- Main article: Guyferd/Gallery.