Ridley is a high ranking space pirate general that has an appearance of skeletal dragon.
Major Story Arcs
Before the Events of Metroid
Not much is known about Ridley's origin, including if he had any military training.
Ridley conducted a raid on the Star Colony K-2L, with the main goal being to steal the planet's Afloraltite. During the raid a three year old girl named Samus Aran tried to befriend Ridley. Despite feeling pity for the child, the space pirate general decided to kill the child, but Samus' Mother protected her with the cost being her life. During this Samus' father destroyed what the space pirates were after, but died in the process. Ridley was in injured in the wreckage and survived by eating the flesh of deceased humans.
The years past and Ridley established a Central Command Center beneath the planet Zebes. After Ridley and his forces destroyed most of the Chozo civilization on the planet, Mother Brain was designated supreme leader of the space pirates. As fate would have it Samus and Ridley met again; this results in Samus suffering from posttraumatic stress disorder on the site of Ridley. He torments Samus further by saying he survived by eating the flesh of dead humans and could have eaten her mother, resulting in him absorbing some of Samus' Mother's cells. Samus recovered with the help of her friends and stopped the space pirates plan. Ridley later killed Gray Voice for trying to shut down Mother Brain.
Ridley confronts Samus during her Zero Mission and is defeated by the bounty hunter. Samus later on fights a robot built in the likeness of Ridley.
Ridley was wounded beyond repair, but was still alive after it seemed he was killed by Samus. He was infused with machinery, by the space pirates, and became Meta Ridley. His transformation reached its final stage in development when the Orpheon made it to Talon IV's orbit. Ridley encountered Samus again when the Queen Parasite escaped and the Orpheon was going to explode. Ridley left the Orpheon and flew to the planet below, only to have Samus follow him. Samus saw her enemy fly over the Phendrana Shoreline, possibly to alert the pirates on the planet.
When Samus was attempting to open the Artifact Temple Ridley flew down and destroyed the Chozo Totems, preventing Samus from reaching the crater. The two rivals met in combat yet again. At the battles end the Chozo Totems blasted Ridley into the crater.
Metroid Prime 3
Despite seemingly falling to his death, Ridley survived the experience. Prior to the events of Metroid Prime 3 Dark Samus managed to use the power of phazon to mind control a pirate homeworld, With Meta Ridley included. Meta Ridley played a role in the Norion invasion where he fought Samus yet again.
Samus first saw him destroy a squadron of Federation Marines. Ridely tried to attack Samus while she was going through a morph ball tunnel, but she managed to escape. Ridley then ambushed Samus when she activated Generator C. He intended to crush Samus, but this lead to them falling through the glass floor and down the Generator Shaft. Samus manages to deliver several shots into the space pirates throat and was rescued by Rundas.
Ridely survived this encounter and traveled back to the Pirate Homeworld where he became the Pirate Seed's Guardian. The large amounts of raw phazon that Ridley received transformed him into Omega Ridley. He encountered Samus at the Leviathan and was defeated. Unlike most Leviathan Guards Ridley did not disintegrate possibly meaning he escaped.
Ridley did manage to survive the events of Metroid Prime 3 and appeared once again, but this time in an organic body. He was sent to capture the baby metroid on Ceres Space Colony, where he killed all the scientists and waited for Samus's arrival. Once Samus arrived Ridley attacked and Samus returned fire. Ridley was forced to activate Ceres' self destruct sequence and escaped with the baby metroid.