Ridley (Metroid)
Ridley's status within the ranks of the Space Pirates is unclear, with some sources stating that he is the leader of the entire Space Pirate race, whereas others portray him as simply the Pirates' military commander or even a mere enforcer within the Pirate military ranks, subservient to Mother Brain or Space Pirate High Command. Regardless, he is consistently depicted as a ruthless and cunning tactician who never passes up an opportunity to bring his considerable ferocity to bear on the battlefield, opting to overwhelm his opponents with an unwavering onslaught of attacks from his mouth, claws, and tail. He is also incredibly cruel, actively taking pleasure in the killing and torment of others; at one point in the official manga he taunts Samus by claiming he may have devoured her mother's corpse after killing her, and a Space Pirate log entry in "Metroid Prime" notes that being the mainstay of the Pirate security force is "a job he will certainly relish."
Mother Brain
The Boston Phoenix editors Ryan Stewart and Mitch Krpata named Mother Brain the fourth greatest boss in video game history, stating that while she had triumphant roles in "Metroid" and "Captain N", she didn't come into her own until "Super Metroid". They cited the overall quality of the ending for why she was so notable in this role. GameDaily listed Mother Brain as the 12th best evil mastermind in video games. GamesRadar editor David Houghton listed Mother Brain as one gaming's most hideous mums, describing her as looking like a "turd on a stick jammed into the top of a long-dead chicken." In explaining why "Metroid" was among gaming's greatest games, GameSpot editor Avery Score cited the battles with Mother Brain and Kraid, describing the battles as epic. Fellow GameSpot editor Giancarlo Varanini described Mother Brain as "appropriately disgusting". GamePro listed Mother Brain as the sixth most diabolical video game villain, describing the battle with her as one of the most notorious and epic assaults in gaming history. UGO.com listed Mother Brain as one of the runners-up for the "Miss Entertainment", commenting that she has sadly diminished in her attempts to thwart Samus, though they hope that she returns. Mother Brain is also featured in the ongoing GameSpot's All-time greatest game villain. In 2011, "Complex" ranked her as sixth on the list of "most diabolical video game she-villains".