Rodan first emerged in 1956 from a giant egg that lay underground in a mountainside. A group of miners had dug up and released a swarm of ancient bugs known as Meganulon. Once hatched the infant Rodan began feeding on the insects. It took only days for Rodan to reach its full size. It grew large horns on the back of its head and sharp serrated spikes on its chest. Rodan's skin is dark brown in color, although after turning into Fire Rodan in the Heisei film Godzilla vs. Mechagodzilla II Rodan's skin turned brick red. In the Showa and Millennium eras Rodan stood as tall as Godzilla but in the Heisei era Rodan and Fire Rodan stood only about 2/3 as tall as Godzilla. In the Heisei era the prominent rows of spines on his belly are replaced with overlapping ridges of bone and he has three horns on his head instead of two (the outer two curve outwards and the center curves up) as well as a wider beak and a more predatory face. Millennium Rodan looked more like the Showa version as it retained the Heisei era ridges of bone on its chest. It also had only two horns again, and its color is similar to the Showa version.
Rodan has layers of spikes on its chest that can be used as a weapon. In the film Ghidorah, the Three-Headed Monster Rodan slammed into Godzilla at full speed and its chest colliding with Godzilla's head to send the behemoth crashing to the ground. Rodan was once one of the fastest known Kaiju but now unfortunately he is one of the slowest flying Kaiju in the series, flying at mach 1.5. The Heisei incarnation flies at mach 3 and others such as Megaguirus fly at mach 4. But one thing most other flying Kaiju lack is Rodan's ability to emit sonic booms from its body, destroying any and all structures in its path. Sometimes called merely hurricane winds, it is clearly visible in Godzilla Final Wars that Rodan can choose to emit the sonic booms, as demonstrated when it flew over the ship "Rumbling" and released a sonic boom destroying the air craft.
In the 1956 film Rodan was given another weapon that was never used again, a concentrated blast of wind from its mouth. This ability was most likely never used again because it was too much like Godzilla's atomic breath. An in-universe explanation can be that the Rodans from the 1956 film died in a volcano, leaving their one and only offspring to survive throughout the entire Godzilla series. The infant lacked the ability to fire a concentrated blast of wind. Fire Rodan was able to fire a uranium heat beam from its mouth, an ability acquired from Godzilla. Fire Rodan could also instill energy in others by sacrificing itself, putting its life force into another being to bring them back from the dead.
In the 1956 film Rodan, two Rodans were unearthed and awakened by mining operations in Kitamatsu along with a swarm of prehistoric insects called Meganulons. After devouring several people and reducing Sasebo to ruins, one Rodan is maimed in a bombardment of their nest in Mount Aso and falls, into a volcanic eruption triggered by the attack. The other Rodan, in a doomed attempt to save its mate, flies into the mouth of the volcano as well. Also, as with Godzilla, the American version differs from the original Japanese release by more than simple matters of language translation; the original Japanese version is much darker in tone. It also has one of the Rodans damaged by a jet fighter, hindering its ability to fly at supersonic speeds.
Rodan went on to cross over into the Godzilla series. Rodan, resurrected by volcanic gas accumulated in the crust, emerges from a volcano in Ghidorah, the Three-Headed Monster first to do battle with Godzilla, then after some persuasion by Mothra, Rodan helped Godzilla and Mothra defeat King Ghidorah. After this point Rodan was no longer a monster of destruction, it was an ally of Godzilla, who after this point turned good as well. Rodan appeared with Godzilla again in Invasion of the Astro-Monster, where both were mind-controlled by Xilians to destroy Earth's cities. After the mind control was broken on them, they attacked King Ghidorah defeating the creature once again. Both Godzilla and Rodan were plunged into the sea, Godzilla would go on to fight other Monsters, while Rodan was collected with all of Earth's other Monsters and placed on Monster Island.
In Destroy All Monsters, the monsters of Monster Island including Rodan were used by aliens to wreak havoc on Earth via mind control, this time by the Kilaaks. Again the mind control was broken and the monsters fought King Ghidorah, this time killing the monster once and for all. Rodan was then placed back on Monster Land to live out his days in peace. Rodan would only appear again in the Shōwa series in stock footage used for Godzilla vs. Gigan, Godzilla vs. Megalon and Terror of Mechagodzilla.
Rodan in the Heisei series appeared in Godzilla vs. Mechagodzilla II, where he sought to protect Baby Godzilla, whose egg was in the same nest as Rodan. Heisei Rodan, while the suit was much bigger and heavier than the Showa version, is notably much smaller relative to the larger version of Godzilla, standing only about 2/3 as tall as the other monster and having a wingspan 1/2 Godzilla's height.
After being defeated and left for dead by Godzilla, Rodan was revived by the psychic song of an ancient plant that had covered Baby Godzilla's egg. Godzilla's radiation mutated Rodan, changing his colors from brown and tan to brick red and light yellow/gold. Fire Rodan also gained a purple colored uranium heat beam similar to Godzilla's nuclear pulse. His beak is powerful enough to break through boulders. Like the Showa version, Rodan seems impervious to Godzilla's breath but only to an extent, being hit several times and not seeming affected until later in the battle.
Rodan played a vital role in the film's climax, sacrificing his own life to revive Godzilla by transferring his life-energy to him. Godzilla then destroyed Super-Mechagodzilla as retribution for Rodan's death.
In the 2004 film, Godzilla: Final Wars, Rodan is used as a weapon of destruction by an alien race called the Xilians via mind control. He appeared alongside an all-star cast of classic Showa monsters, as they wreaked havoc on the major cities of the world and were sent to fight Godzilla. Rodan attacked New York City while under the aliens' control.
Rodan, King Caesar, and Anguirus are pitted against Godzilla at Mt. Fuji. He successfully defeats all three monsters. King Caesar, Anguirus and Rodan are then left in a heap at the base of the mountain. Godzilla did not kill his fallen foes as a nod to their status as allies of Godzilla during the Showa era. This is in contrast to the remaining majority of the monsters seen in the film, all of whom, aside from Zilla, were enemies of Godzilla during the Showa era, and were slain either by Godzilla, the Gotengo, or the mutants who were part of an anti-monster task force near the beginning of the film.
Ghidorah, The Three-Headed Monster
Invasion of Astro-Monster or Monster Zero (US release)
Destroy All Monsters
Godzilla vs. Gigan (Stock Footage)
Godzilla vs. Megalon (Stock Footage)
Terror of Mechagodzilla (Stock Footage)
Godzilla vs. Mechagodzilla II
Godzilla Final Wars