Metroid has produced several unique bosses to face off against the protagonist of the franchise, and as the Metroid series progressed, the villains became stronger and tougher. The games offer players the chance to test their skills as these new bosses all presented a sterner challenge to the heroine Samus Aran.
Even though the Metroid franchise introduced new bosses it did not kill off the old enemies that fought against Samus—rather, the old bosses grew in strength to pose another challenge. These characters evolved from their base form to become stronger, while some of the other bosses rebuilt themselves by becoming cyborgs.
9 Gorea
The main villain from Metroid Prime: Hunters, Gorea was a terrifying malevolent being who sought to destroy civilizations as a source of entertainment. He was responsible for the destruction of the Alimbics, as he drained them of their life force and used their weapons against them, putting an end to their civilization.
During Samus’ fight with Gorea, she initially struggled to injure the villain. After she was able to damage and break him apart, Gorea revealed his second form to be a gaseous one. Samus struggled to defeat Gorea in this form switching to different weapons until she used the Omega Cannon to defeat Gorea completely.
8 Emperor Ing
Emperor Ing is featured in Metroid Prime 2: Echoes as the final and main villain, he is the leader of the Ing military and the strongest of all the Ings. Emperor Ing mutated and strengthened itself with Phazon energy and the Light of Aether. He can create powerful attacks by combining light and dark energies.
Samus has to battle this villain in all his three forms. Emperor Ing in his first form has a large spherical head and a stationary body, while in his second form, Emperor Ing encloses himself in an impregnable magnetic shell. His third form which offers him more mobility shows his heart is unstable due to him absorbing excess Phazon and Light of Aether.
7 Queen Metroid
The Queen Metroid is a destructive parasite that likes to destroy anything in her path and is the main villain from Metroid 2: Return of Samus and Metroid: Samus Returns and also the penultimate boss in the game Metroid: Other M. Throughout the Metroid franchise there have been only two Queen Metroids.
The Queen Metroid is the largest and the most powerful specie in a Metroid’s lifecycle. Only a few Metroids with a specific coding can become Queen Mothers, they are capable of laying eggs and are solely responsible for reproducing other Metroids.
6 SA-X
SA-X is the main villain from Metroid: Fusion, it is an X parasite that mimics her battles suit, SA-X is a replica of Samus. SA-X was created after Samus’ Power Suit was infected when she came in contact with X. After she escaped from Quarantine Bay, she sought to kill Samus.
SA-X was initially a difficult challenge for Samus. She could not defeat the SA-X because its weapon, the Ice Beam, and Samus had a high vulnerability to cold due to the Metroid vaccine. She would have to run or hide from SA-X. Eventually, she defeated SA-X using Wave Beam.
5 Mother Brain
Mother Brain is the main villain from Metroid, Metroid: Super Metroid, and Metroid: Zero Mission. She is Artificial Intelligence created by the Chozo whom she later rebelled against. She appears in several games in the Metroid series as a recurring villain.
Her goal was to bring order to the world by resetting everything to zero, effectively destroying the Metroid universe and all civilization. She is a challenging opponent for Samus as she can regenerate her life and self-heal her injuries. Her intellectual capacity increased the potency of her attacks against Samus and the Galactic Federation.
4 Kraid
Kraid is a major villain in the Metroid Series. He appears in Metroid, Metroid: Zero Mission, Metroid Prime, Super Metroid, and Metroid Dread. He is one of the biggest opponents has Samus encountered and many players consider him to be the muscle of the pirates.
Kriad’s body is his biggest asset. All his weapons are from his body parts which he can generate infinitely, and his body is also immune to lava. Kraid can shoot projectiles and small fireballs from his mouth. He is one of two villains players have to defeat before they can fight Mother Brain.
3 Raven Beak
Raven Beak is one of the adoptive fathers of Samus and a recurring villain in Metroid: Return of Samus and Metroid: Samus Returns. He is the main protagonist in Metroid Dread. He is the mastermind behind the massacre of the Thoha tribe, which ensured the continued survival of the X parasites.
Raven Beak has a merciless, ruthless, and manipulative nature. Hence, he tricked Samus to awaken her Metroid powers which he wants to use to create clones to conquer the Metroidverse. He is obsessed with power and would kill anyone who opposes him.
2 Metroid Prime/Dark Samus
Metroid Prime is the main villain of the first game in the Metroid Prime trilogy. She was reborn as Dark Samus the main villain in Metroid Prime 2: Echoes and Metroid Prime 3: Corruption. Metroid Prime is a being that mutated due to high exposure to Phazon.
Dark Samus came to be after it absorbed Samus’ DNA and her Phazon Suit, she is a powerful adversary that can absorb large quantities of Phazon. At one point she became immune to all forms of attack except for a huge blast of Phazon.
1 Ridley
Ridley is one of the most recurring villains and the main antagonist in the Metroid series, but he is only the main villain in Metroid: Samus Returns. He has a ruthless and sadistic personality and takes delight in anarchy, destroying the colony K-2L.
Ridley has great resiliency, eating human flesh to regenerate and self-heal his injuries. He was responsible for the deaths of Samus’ parents. Ridley fought with Samus several times and was able to survive until she completely defeated Ridley in Zebes.