The Synopsis of Ridley, the beastly leader of the space pirates from the Metroid franchise.
While his species' true name is currently unknown, he is often regarded as a "space dragon" (a name taken from the Nintendo Comics System). Next to nothing is known of his pre-military background (if in fact he even had any), but it is safe to say that he made his way up the ranks until finally he was bestowed the designation as leader of the Space Pirates in battle.
He also appears to have considerable favor among High Command. Ridley's introduction takes place on an Earth-established Colonial Planet, known simply as K-2L; where he conducts a massive raid in order to restock fuel and supplies and plunder, and also allows his soldiers to cut loose and destroy whatever they want. It is also on K-2L that Samus Aran (as a 3-year-old) first encounters him. Samus attempts to befriend Ridley, but being the sadistic monster he was, he tried to kill Samus.
However, her mother pushes her out of the way of Ridley's attack at the cost of her life. Meanwhile, Samus's father destroys the supplies the pirates were after and is also killed in the blast. Ridley also appears to be injured by the wreckage but survives. However, he never imagined that he created his own nemesis in Samus.
Years later, Ridley returned to Zebes, to establish a Central Command Center beneath the planet's surface. His forces annihilated the native Chozo Colony established on its surface before carrying out these orders. Also, he killed Grey Voice when the latter tried to shut down Mother Brain (he pretended to join the Space Pirates so he would try and get close enough to Mother Brain to shut her down, realizing her treachery). Up until this time, the Galactic Federation disregarded Zebes as a low priority, class XIII Wanderer Planet.
This changed when the Space Pirates stole a specimen of the dangerous Metroid and word came that the Pirates planned to clone an army of the creatures in their base of operations beneath its surface. The Federation was quick to send its fleets into battle, in order to remove the threat. Ridley personally led many battles against the Galactic Federation's forces, over control of the planet, and defeated everything the Federation Police Force had to attack with.
However, sometime after these battles, he left Zebes on his flag-ship as well as the Space Pirate Mothership, to fight the fleet of Adam Malkovich, only to later receive a distress signal from Zebes after Kraid's defeat and return to do battle with Samus Aran, a Bounty Hunter the Federation had sent to destroy Mother Brain. While the great Space Dragon threw everything he had at his old-yet-new nemesis, he did not come out the victor, and instead found himself nearly destroyed.
Ridley eventually confronted Samus in the depths of Norfair. In Metroid, this battle took place in MiniBoss Hideout II, whilst in Zero Mission, it took place in Ridley, an area named after him. Both are the same area, just renamed for Zero Mission. In Metroid, Ridley is about Samus' height, if slightly taller, and merely hops around throwing zigzagging fireballs at her. Samus can fire almost anything at him and he gets hurt. Once Samus defeats him, 75 missiles are added to her maximum amount. In Zero Mission, however, he is much more difficult. Ridley flies around and tries to kill Samus with his "classic" attacks - tail swipes, plasma breath, fireballs, and claw slashes. After Samus defeats him, she is allowed to leave with the Unknown Item (Gravity Suit) that had started the battle.
After Samus explores the Space Pirate Mothership and recovers her lost Power Suit, she eventually stumbles onto the Ridley Robot, a mechanical construct inspired by Ridley that she must destroy in order to leave the ship. After its destruction, it activates its self-destruct mechanism, which obliterates the mothership in a massive explosion. Fortunately, Samus is able to escape just before the ship detonates.
Ridley, after sustaining severe injury, was wounded beyond fighting capability. However, a scan in the Space Pirate Frigate Orpheon, in the later Metroid Prime game, indicates that he, in fact, survived the attack.
Space Pirates, by order of High Command, recovered his fatally-crippled body and infused it with machinery, reconstructing Geoform 187 into "Meta Ridley". On Tallon IV, Meta Ridley apparently visits many of the Space Pirate bases, first going to the Phendrana Drifts to see the Pirate base, and then flying off towards the Phazon Mines, where he presumably remains until Samus arrives. They later engage each other in battle at the Artifact Temple. At its conclusion (after which his life-bar is depleted), the Chozo Statues blast Meta Ridley and send him hurtling to his death in a fiery explosion.
Despite his fall, he somehow survived, possibly due to the Space Pirates salvaging him, or possibly due to the strength of his cyborg modifications. In any case, Meta Ridley reappeared on Norion during the Space Pirate attack on the Galactic Federation Marine Corps, where Samus fought him once again. He first tried to attack Samus while she was invulnerable Morph Ball mode, but Samus managed to use her Morph Ball Bombs to escape. He then ambushed her at Generator C, sending both of them down a deep shaft, with the intention of crushing Samus at the bottom.
Despite the enclosed environment of the fight, Samus was able to defeat him once more and after delivering several shots directly into his throat, left him for dead before being saved by Rundas. Ridley, however, survived this battle and then went to the Pirate Homeworld and was attracted to the Leviathan (implied in the Infant Leviathan scan), where he was corrupted and transformed into Omega Ridley. Samus later encountered the creature in the Leviathan and defeated him. Interestingly, unlike the other Leviathan guardians, Ridley is never seen disintegrating.
By the time of Samus's mission on SR-388, Ridley had regenerated most of his organic body and shed half of his cybernetic enhancements. Known as Proteus Ridley, he ambushes Samus and the last infant Metroid on SR-388, intending on capturing the Metroid. He and Samus duel once again, with Samus being aided by the Metroid. She eventually triumphs, blasting him in the chest multiple times and leaving him unconscious.
Ridley would survive this encounter, shedding the last remains of his cybernetic enhancements and regaining his organic body. He destroys the Ceres Space Colony and steals the last Metroid. He and Samus have yet another skirmish, but just before Samus is mortally wounded Ridley leaves as the space station's self-destruct sequence begins. He flies off to the rebuilt Space Pirate base on Zebes, where they plan to clone Metroids and make an army of them for galactic domination.
Ridley is once again equipped with his "classic attacks" (as a matter of fact, Super Metroid was the first game to feature these attacks) when Samus finds him in his lair in the deep, central part of Norfair. Samus must defeat him again as one of the bosses to unlock access to Tourian. With the loss of the armor plating from his previous form, he is now much more vulnerable to attack. His previous form demanded that he be shot in the chest or mouth, but he is now vulnerable to both Missile launchers and Charge Beams from any angle; however, Ridley has the ability to swat Missiles away with his whip-like tail.
After Samus defeats Mother Brain, Zebes explodes. This event marks the death of the original Ridley, with his subsequent appearances being clones or imitators.
After Samus had defeated the Space Pirates and destroyed Zebes, a corrupt Galactic Federation science team collected samples of alien DNA from Samus's suit and cloned them in their labs on the Bottle Ship. Unknown to them, one of the samples was Ridley's DNA.
Ridley's clone was born as a small, bird-like creature, which the science team dubbed "Little Birdie" and kept as a pet. One day, the clone played dead to lure in a scientist into its cage and proceeded to eat him.
Samus first encountered Ridley's clone in his "little birdie" form in the Biosphere, witnessing him attempt to eat a large fruit. Though she dismisses him as harmless, she hears his cries disturb the Kihunter nest, causing the nest's denizens to attack Samus. After she destroys the Kihunter hive, she sees Ridley's clone again, ravenously devouring Kihunter honey. She muses to herself that the creature had manipulated her.
The clone's metamorphosis, hastened by his endless appetite, transformed him into a form known as the Mystery Creature. The Mystery Creature was more reptilian in looks, bearing a long tail ending in a sharp spearhead and a coat of white fur, a vestige of the "little birdie." The Mystery Creature ambushed Samus, holding her in place while his bioform minions attacked the troops. She eventually warded him off, but he retreated to the Pyrosphere.
The clone's final encounter with Samus on the Bottle Ship was in the depths of the Pyrosphere. He attacks Samus's compatriot Anthony Higgs near a lava vent, but after she destroys the vent, he finally reveals himself as Ridley, much to Samus's horror. However, when he knocks Higgs into the lava below, she battles him once again and triumphs. The clone survives, however, and flees to another part of the ship. He is last seen as a withered husk near the Queen Metroid's containment area, his life force sucked dry by the Queen Metroid. After the end of the incident on the Bottle Ship, BSL recovers his body and takes it to their base near SR-388.
Like some recurring nightmare, Samus found the clone's frozen husk located within a frozen stasis chamber upon the Biologic Space Laboratories research station's main deck. To her relief, he was frozen successfully and could not move or provide any kind of terror in this state. Unfortunately, his inability to move led to his eventual infection by an X-Parasite. This parasite cracked the ice open and shattered the clone. However, the parasite absorbed Ridley's DNA and assumed Ridley's appearance, regenerating his body through itself and making him even stronger than before. Known as Neo-Ridley, the parasite attacked Samus, only for her to subdue him and absorb his parasite form into her gun, reacquiring the Screw Attack. With the parasite's destruction, Ridley is presumably gone for good, unless his DNA still exists within Samus' suit after absorption.
In other media
Super Smash Bros. series
Ridley has appeared in all Super Smash Bros. games to date, barring the 3DS game. He has been a highly suggested playable character despite never being playable due to how big he is. Masahiro Sakurai has mentioned that he thought about including him, but would have to shrink his size in the game, later coming to the conclusion that it wouldn't be Ridley if they shrunk him, and that it would just look weird, which led into multiple people making mods on the game where they could play as Ridley.
Super Smash Bros.
This is no doubt his most minor role in the entire franchise, he is seen in the background as a pixel art during the level Planet Zebes and does nothing more.
Super Smash Bros. Melee
In the opening scene of Melee, he can be seen fighting Samus, he breaks through a wall in order to reach Samus and confronts her in the corridor. This is based on the Ceres Base Colony fight at the beginning of Super Metroid.
Super Smash Bros. Brawl
In this game, Ridley has his biggest role in the Super Smash Bros. series yet, as a major antagonist in the Subspace Emissary.
He first ambushes Samus when Pikachu and Samus walk around in the Research Facility. He tortures Samus by dragging her onto the walls, but Pikachu manages to electrocute Ridley with a thunderbolt and temporarily manages to paralyze him. The three then engage in battle.
As a boss, he uses very agile and fast moves. His arguably worst moves are his claw attacks, and a simple backflip, which slashes and throws the player up. He also possesses an attack where he flies off the screen and proceeds to plummet toward the ground in a smash attack that rarely hits, but delivers decent damage if it does, and can follow it up with a more unexpected second fly-crash that has a wider range and greater damage.
He has another what looks almost like Rayquaza's extreme speed attack where he charges from one of the corners and knocks the player away if it hits. It can unexpectedly hit, because of how fast it is.
Another of his attacks is when he scraps his sharp tail against the player and scraps them along. It can do some large damage and long knockout depending on the difficulty.
But his killer move is when he flies away for a while, and then unexpectedly comes back and knocks out the player if it hits, this is the most dangerous for sure, considering it can be hard to track because of how fast it comes and does a large amount of damage and knockback.
He later appears in the game as Meta Ridley, where he pursues the Falcon Flyer to seek revenge on Samus and Pikachu. In general, Meta Ridley has more devastating attacks, and the more damage he suffers, the farther he flies from the Falcon Flyer, making the battle harder. The battle is also timed at two minutes. Meta Ridley takes advantage of the Falcon Flyer as well, either crashing on the Falcon Flyer to instantly drag it from the blast line or send it gradually dropping as he shoots fireballs before sending it back up.
Ridley is later resurrected, both in his organic and Meta Ridley incarnations, by Tabuu as bosses in the Great Maze.
Super Smash Bros. for Wii U
Ridley appears as the stage boss of the Pyrosphere. He is aggressive and will fight against anyone on the stage, the player that defeats him, gets an extra point, but the players can also use him as a powerful minion, by hitting him multiple times, when that has happened, he won't try to kill the leader, but if someone else makes him their minion, he will try to defeat the others again, his moves are quite similar to the moves he had before, but the design on them may be a bit different. But this time he has a move where he breathes big flames of fire, and another one where he does some close-up combat.
Super Smash Bros. Ultimate
For the first time ever, Ridley is a playable character in Super Smash Bros. Ultimate, and is the second new fighter (following the Inklings) introduced for the game. As for his current design in the game, he is the largest character to date, and the first character to be larger than Bowser.
Ridley's fighting style is incredibly vicious, with savage moves such as claw swipes, tail attacks, grabs, and fiery breath. For his Final Smash, he knocks his enemy into Samus's ship, then fires a stream of plasma breath, destroying Samus's ship and the victim.
His alternate costumes reflect his various designs across the Metroid series, including one based upon Meta Ridley.
In "Adventure Mode: World of Light", Ridley has four spirits based on four of his forms. His first Spirit, based on Ridley himself, is unlocked after clearing his Classic Mode. Meta Ridley can be unlocked by clearing the challenge of using Ridley's Skewer attack four times in a single battle. Little Birdie is a Support Spirit, with its Spirit Battle being against a tiny Ridley, but he grows giant-sized upon having enough damage taken. Finally, Omega Ridley is a legendary class Attack type Primary that increases the fighter's weight. In this Spirit Battle, Ridley is coated in metal and breathes fire via curry.