The Cranassians are the villainous force from the Raiden series.
These are alien invaders who want to conquer our world, starting an invasion in the year 2090. The World Alliance Military captures one of their vessels, and based on it they create the Raiden series of fighters, in order to counter the Cranassian invasion. The World Alliance Military has been successful in their fight against the Cranassians, having defeated them four consecutive times, though the Cranassians don't show signs of ever giving up.
In 2090 A.D., Earth has been exposed to invasion of an alien force known as Cranassians. Amidst the intense war Earth's military alliance gathered their best best scientists and engineers to create supersonic jet fighters from downed alien fighter crafts. The newly created supersonic fighters are code named, 'Raiden'. But Raiden's powerful performances were too much for majority of pilots' body to handle, and only two Raiden were made because there were only two humans who can physically measure up to Raiden's excessively powerful performance. The two pilots, riding on the dual supersonic fighter jets, scrambled to destroy Cranassians, with the prayers of people of Earth weighing on their shoulders...
It's been three years since the war between Earth and Cranassians ended in Earth's triumph, aided by Earth's newest weapon code named Raiden, two extraordinary powerful supersonic jets made from downed Cranassian aircrafts. However, Cranassians somehow managed to regroup and recoup from their losses, reorganized their shattered forces into vaunted military once more and again proceeded to invade Earth: the Earth-Cranassian War has become even more devastating than the previous war. With slowly giving grounds to revived alien invaders, The Earth's military alliance enhanced Raiden's maneuverability in addition to equipping the dual jets with the newest arsenals: Plasma Lasers and Cluster Bombers. Code named Raiden II, the dual jets that vanquished Cranassians once again take wings and launch to Cranassians with Earth's prayer for her existence behind them...
Raiden III and IV
III and IV have no storyline: just simply defeating the attacking Cranassians.
Raiden V: The Reboot
In Raiden V, it is revealed the actual Cranassians have already been extinct for a very long time and the Energen Crystals contain their souls and still carry their will. Whenever the Crystals arrive on a inhabited planet, they will infect the planet's weapons and slowly change the composition of the planet's atmosphere, until the planet becomes uninhabitable and all life on it is extinct. At the same time, they will also accumulate water and, once life is extinct, begin to restore the atmosphere so that life on the planet can begin anew.
Their forces are comprised of various military machines and aircraft, all of which are controlled by a red crystal(called Energen Crystal) which also serves as a power source. The crystals themselves are apparently sentient, since whenever their vessels are destroyed, the crystal will leave the machine and fly away.
According to the Raiden Fighters spinoff series plot, during the Earth-Cranassian Wars(also referred to as Crystal Wars), Earth's World Alliance Military forces managed to capture some Cranassian prisoners of war. One of prisoners tells the story:
Cranassians are humanoid alien race hailing from Planet Cranassia. Since 19th Century Planet Cranassia had been involved in constant wars, conflicts and strifes. Then came the 5 Great Global Wars that eventually destroyed the Planet Cranassia. Having destroyed each others' nations and their planet, Cranassians of different warring states are forced to forge temporarily alliance to seek a new home.
Thus began their long, arduous journey through space and time.
Finally in 2090 A.D. (event of the first Raiden), Cranassians reached The Solar System and discovered a very habitable 'Green Planet' called Earth. Cranassians, exhausted of resources and strengths after long and tortuous journey through space, decided that Earth would be theirs for the taking.
Furthermore, the POW confessed that during the 5 Great Global Wars of Cranassia existed a squadron of fighters with extremely high-performance. These extremely powerful fighters turned out to be distant protoypes of Supersonic Attack Fighter, which would later become World Alliance Military's Raiden Mk-II and Mk-II Beta.
These prototype fighters are called Raiden Fighters.
Raiden Fighters, Raiden Fighters 2: Operation Helldive and Raiden Fighters Jet depict the first three Great Global Wars of Cranassia out of 5.
- While Raiden III and IV had practically no plot, Raiden V acts as a soft-reboot of the series, explaining the Cranassian's origins (much in the same way the Bydo is explained in R-Type Final) and retconning previous plot points like the connection of the Raiden Fighters spinoff series with the main series.
- The end VGM of Raiden V is titled, 'The Battle that Never Ends', indicating that the franchise isn't coming to an end any time soon.