Ridley (Metroid)
One of Adam's final missions to Samus is to finish off Ridley, whom Adam fears might be more dangerous than the Metroids if left unchecked, and claims Samus is the only one capable of stopping him. However, Samus later discovers his corpse after he is killed, having had his energy drained by the Queen Metroid on the Bottle Ship. His mummified corpse turns up again in "Metroid Fusion" on the BSL station, after having apparently been removed from the Bottle Ship by the Galactic Federation and placed in a sub-zero storage room for further research (potentially into further bioweapon applications). It is later infected by an X Parasite, allowing it to gain the ability to transform into Ridley's likeness, known as . Samus later defeats the Ridley mimic and absorbs its Core-X, regaining her signature Screw Attack. What was left of the cloned Ridley's remains were destroyed along with the X when the BSL station crashed into SR388.
Characters in the Metroid series
The Metroid larva is chronologically the last Metroid of its race following the events of "" and "". Samus describes how a Metroid larva hatched from an egg and immediately imprinted upon her, believing her to be its mother. She brought the larva to Ceres Space Colony, where scientists learned that they could harness its power. Just after she left the colony, she received a distress call and returned to find the scientists dead and the larva stolen. The Baby Metroid is used as the driving theme of the game as Samus tirelessly searches through Zebes and eventually the Space Pirate's base on Tourian for her Metroid hatchling. Once encountering the enlarged Baby Metroid in Space Pirate clutches, it attacks Samus and nearly drains all her energy. During the final battle against Mother Brain, the Baby Metroid comes to aid of Samus by recharging her energy, but Mother Brain destroys it in retaliation. Samus avenges its death by destroying Mother Brain with an extremely powerful weapon given to her by the Metroid. After a planet-wide self-destruction, Samus for once mourns the death of a Metroid.