Guiron is an alien monster that normaly walks on all fours, but can also stand on two legs when the situation requires. It is an unusual looking creature, with tough gray skin, a small mouth, sleepy looking eyes and a low, groaning bellow. The most unusual feature of this beast's anatomy, however, is the gigantic blade that it sports on its head, which is nearly as long as its body.
Guiron is mostly a melee oriented kaiju. Almost all of his abilities revolve around the massive blade he sports on his forehead. It is strong enough to reflect a blast from a Space Gaos and cut Gameras shell. When he can't use his blade Guiron resorts to his secondary attack. A pair of four shurikens stored in two circular indents in the blade. Guiron can guide these shuriken using telepathic waves. They were sharp enough to cut right through Gameras arms.
Guiron acted as the guard dog of two brain-eating space women, the last of a dead civilization on the planet Terra. The aliens guided him with a mind control device. Guiron proved his combat prowess by effortlessly defeating a Gyaos, reflecting its sonic cutter beam and literally slicing it to pieces with his blade. Guiron later fought Gamera, and nearly killed him as well. After a long fight, Gamera eventually managed to defeat the knife headed beast by flipping him upside down - his blade stuck in the earth - then igniting a missile that had gotten stuck in his circular indents, blowing his head off and killing him.
Gamera vs. Guiron (ガメラ対大悪獣ギロン Gamera Tai Daiakujū Giron, Gamera vs. Devil Monster Guiron, released in the U.S. as Attack of the Monsters), is a 1969 kaiju ("monster") genre film, the fifth entry in the original Gamera series.
While scanning the skies through their telescope, two young boys, Akio and Tom, spy a spaceship descending into a nearby field. Stunned, bewildered, and bemused, they tell Akio's mother what they have seen, but she dismisses their story as childish nonsense. The next day, the two boys—with Akio's younger sister, Tomoko, in tow—bicycle to the site to investigate. Enthralled, Akio and Tom manage to steal into the spaceship. But then, without warning, the ship takes off, leaving Tomoko behind. It soars into outer space...toward a field of asteroids, which sends the boys into panic. However, Gamera (obviously aware of the boys' plight) appears and clears a path for the ship through the asteroids. The spaceship, flying near the speed of light, leaves Gamera behind and transports the boys to an unknown planet, where it lands on the outskirts of an alien city. Suddenly, a silver "Space" Gyaos appears, menacing the ship and the two young boys. Just before the creature attacks, a second, bizarre monster—whose head resembles a knife—emerges from an underground lair and attacks the Space Gyaos. After a violent battle, the knife-headed monster kills the Gyaos by chopping it into pieces.
Barbella and Florbella suddenly turn on Tom and Akio and put them into restraints. Using their super-technological devices, the alien women probe the boys' minds, in the process learning about Gamera—who, they discover (again via stock footage), has a terminal soft spot for human children and is hurtling toward Terra on a rescue mission. The Terran women turn out to be cannibals and plan to feed on the boys' brains. In preparation to extract his brain for their nourishment, the women shave Akio's head. Now, however, Gamera lands on Terra in search of the boys. The women deploy Guiron to attack the giant turtle, and after a brief battle, Guiron renders Gamera helpless, sending it into a lake...unconscious and on its back.