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Proteus Ridley[2] is the final boss of Metroid: Samus Returns and the final incarnation of Ridley's cybernetic form. He was not present in the original Metroid II: Return of Samus.


Following his defeat as Meta and Omega Ridley in Metroid Prime 3: Corruption, Ridley seemingly managed to regenerate most of his original body and removed large portions of his cybernetics. Proteus Ridley's visual appearance reflects the progressive regeneration of his organic body, a process first noticeable when Omega Ridley's purple body became more pronounced and was pushing off the implants he originally gained as Meta Ridley (suggesting his Corruption actually had a healing effect on him).

With the Space Pirates turning their attention to Metroids again, Proteus Ridley traveled to SR388 presumably to retrieve any Metroids. By the time he arrived however, Samus Aran had already destroyed all but one Metroid which had imprinted onto her following its birth.

Proteus Ridley grabbing at the baby as it tries to flee

As if foreshadowing Ridley's appearance, a thunderstorm (accompanied by unsettling music) began as Samus and the baby arrived at the Surface after leaving Area 8. A cave-in blocks off the initial entrance to the main caverns, preventing access to the landing site from the opposite side. Facing her Gunship on the top of a cliff, Samus activates it remotely while the baby curiously approaches it. From a distance above, Proteus Ridley emerges out of the storm clouds and heads straight for the Metroid with the intention of bringing it to the rebuilt Space Pirate fortress on planet Zebes.

At the sight of her nemesis, Samus hurries in his direction. He briefly chases the baby, landing on top of her Gunship, before successfully catching it with his left hand, holding it firmly as he is confronted by Samus.


First phase[]

Proteus Ridley attacking with the arcing-fireball attack during Phase 1

Starting off in the air, Ridley clutches the baby in his metal hand as he battles Samus. His attacks include breathing five purple fire balls in an arc, thrusting his tail below him in an attempt to jab Samus, and quickly slamming onto the ground before taking flight again. If Samus is Space Jumping at his height and above, or climbing the wall with the Spider Ball, Ridley will whip his tail in a wide arc directly in front of him and alter the angle of his fire balls. Ridley's attacks are very powerful, with many taking out a full Energy Tank.

As a consequence of his regeneration, Proteus Ridley has lost much of the protection the metal implants offered throughout the Metroid Prime series, as he can now be harmed by mere Beam weapons shot directly into his exposed organic body. His weak point is both his chest and mouth area, which Samus can take advantage of using Super Missiles, Plasma Beam shots, or the Beam Burst. Regular Missiles are ineffective as they will merely bounce off of him. The Ice Beam can also harm him, but considerably less than her other options.

After taking enough damage, Ridley will recoil and release plenty of Aeion Orbs to refill Samus's Gauge. A cutscene triggers in which he attempts to fly away with the Metroid in hand. Samus jumps onto his tail, stalling him as he attempts to shake her off, but she immediately flies onto his chest with her thrusters and pumps Plasma Beam shots into him. He screams out in pain and releases his grip on the baby, prompting Samus to jump towards the Metroid and grab it as she falls away from Ridley. When he attempts to charge at her, she lands a beam shot on his left wing, sending him crashing into the nearby cliffside and is partially buried under rubble. However, Ridley quickly opens his eye, rises up and engages Samus again for the second phase.

Second phase[]

Samus firing at Ridley with the baby in her hand.

In the second phase, the baby watches the battle at a distance near Samus's Gunship as a storm intensifies in the background. Ridley will now perform additional attacks, some of which are ground-based. When he is located on the ground, he will shoot individual blasts of fire at Samus' position and swipe with his claws if she is close to him; with the latter attack, Ridley may follow up with a second swipe. He takes flight if Samus jumps over him, from which point he will use the previous aerial attacks along with a new one.

The new attack consists of Ridley charging across the area with his entire body and tail extended to the floor, giving this move a wide range. If Samus is close to a wall, he will slam against it and remain still very briefly, though he will turn around instantly if the wall is sufficiently distant. Two of Ridley's aerial attacks from the 1st phase have different properties, such as the tail thrust which now stabs into the ground and releases a wave of spiked rocks when he pulls it out. His ground pounce no longer has him take flight right after and instead switches him to his ground-based pattern.

Once he has taken more damage, more Aeion Orbs will be released from Ridley. A cutscene will then play where he tries to stab Samus with his tail before shielding himself against her attacks as he flies towards her, getting close enough to grab and throw her at a wall. He then pins her on the floor with his left hand and shoots a fire ball at point-blank range, exhausting her. Before Ridley can continue, the Infant Metroid intervenes to save its "mother" and leeches some of his Life energy, but the latter is quickly shaken off. The baby transfers the absorbed energy to Samus, which restores part of her health (equivalent to 2 full Energy Tanks) before the third phase.

Final phase[]

Afterimage effect of Proteus Ridley performing his hyper claw slash during Phase 3

Ridley becomes more aggressive, using all of his previous attacks at a faster rate as Samus continues to battle him with assistance from the baby. He gains three additional attacks: on the ground, he will use his hyper claw slash, while on the air he will shoot a focused fire ball directly under him which releases a fireball shockwave on both sides from the point of impact. The other new attack is Ridley swooping in to grab Samus which, if successful, will trigger a short cutscene where he slams her repeatedly onto a wall before tossing her. This sequence causes high amounts of damage to her, but can be negated if Samus has the Lightning Armor active; in fact, the ability can be turned on at any moment during the cutscene, but will not remove any damage inflicted prior to its activation. Unlike charging with his tail extended to the floor, there's a free space of about the height of the Morph Ball underneath him when swooping in, hence the attack can be avoided by using the Morph Ball. He may also perform his ground slam multiple times consecutively.

The baby helps Samus by draining more energy from Ridley after she inflicts a certain amount of damage to him. Whenever it does, he will shake off the Metroid and lunge himself at Samus, which she can reflect with her Melee Counter as indicated by the white ring emanating from his mouth. Successfully countering it triggers a cutscene where she blasts Ridley in the chest several times with a weapon of her choice, and then climbs up his body before repeatedly shooting down his throat. This does not finish him off however, as the battle continues until Ridley is wounded enough to allow the baby to leech him again, repeating the earlier process a second and final time. This causes Proteus Ridley's cybernetic implants to short-circuit before he falls to the floor defeated.

Alternatively, Proteus Ridley can be vanquished without resorting to the Melee Counter at all: each time the baby finishes draining him, Samus can simply continue attacking Ridley from a safe distance and avoid his lunge.


A Hornoad gnawing Proteus Ridley's discarded mechanical claw

Samus watches an unconscious Ridley before she looks over to the Infant Metroid, prompting her to leave with it in the direction of her ship. Though he is not seen again afterwards in the game, he either regained conscious offscreen or was recovered by Space Pirates, as a Hornoad is seen after the credits gnawing on Ridley's abandoned mechanical claw before it is attacked by an X Parasite.

Based on his following appearance in Super Metroid and to some extent the abandoned mechanical claw in the ending, he removes the rest of his cybernetics before attacking the Ceres Space Colony where Samus donated the baby Metroid for research. With his fully-restored organic body, Ridley rampages the station; despite Samus' efforts to stop him, he successfully abducts the baby and brings it to the rebuilt Tourian on planet Zebes.

Official data[]

Metroid: Samus Returns Official Guide[]

Inhabitants & Eco System of SR388 (p. 23)
"Samus' greatest nemesis makes a return in this game to put a stop to her Metroid eradication. It was Proteus Ridley, Mother Brain, and the Space Pirates that harnessed Metroids for evil during Samus' first mission, and they clearly found it to their liking. Proteus Ridley’s not about to allow Samus to wipe out such a formidable source of power and an equally devastating weapon—not without a fight."


  • As previously stated, Ridley was not originally present in Metroid II: Return of Samus. Therefore, his appearance in the remake Samus Returns is a retcon. Proteus Ridley is one of two new bosses in Samus Returns, the other being the Chozo excavation robot Diggernaut. Additionally, Proteus Ridley, along with Diggernaut and Arachnus, are the only bosses in Samus Returns that are not Metroids.
    • The addition of Proteus Ridley's battle against Samus and the baby, in which the Metroid's intervention prevents the Space Pirate commander from achieving victory, results in a minor inconsistency with Samus's dialogue during the events of Metroid Fusion. She states in the latter game that she owes the baby her life twice over, when in actuality it is now a total of three times (due to the retcon) that the Metroid has saved her. The other two rescues consist of the baby's sacrifice against Mother Brain and its DNA being used to save Samus from the X Parasite's infection.
    • His appearance in Samus Returns explains how Ridley was able to launch a perfectly timed attack on Ceres Space Colony, setting off the events of Super Metroid. It also canonizes the Metroid Prime series, establishing their place as prequels to Samus Returns in the Metroid timeline.
  • It was MercurySteam's idea to add Ridley into Samus Returns as the surprise final boss. Yoshio Sakamoto approved of the concept, believing that fans would love it and it would make the story more dramatic. While there is no direct link between the 2D and Prime series, Proteus Ridley's cybernetics from Meta Ridley were included to preserve a minimum level of consistency in the timeline.[3]
  • Considering the presumably short timeframe between Samus Returns and Super Metroid (in which Ridley appears fully organic chronologically for the first time since Metroid: Zero Mission), it would appear that Proteus Ridley fully recovered from his battle with Samus much more quickly than any previous battle. This suggests that any injuries he suffered during this battle were far less severe.
  • Proteus Ridley's official artwork, illustrated by Raquel Cornejo, features him with his neck and lower jaw both covered in cybernetics. This region of the body differs slightly in his in-game model, with only the back of his neck covered in such materials.
  • Owing to him being a variation of Meta Ridley, several of Proteus Ridley's vocal sound effects are recycled from his Meta form.
  • Samus Returns marks the first time that Ridley has been the final boss of a Metroid game; while Zero Mission features Mecha Ridley as its final boss, it is merely a robot he built in his likeness.
  • His presence in the game was first hinted at in the Overview Trailer, where Proteus Ridley's theme was heard during the Aeion gameplay portion. A glimpse of his hand was also seen in the September 13, 2017 Nintendo Direct, two days before the game's release, with the narrator also hinting at his identity by saying "Vengeance has a name". The same source, when showing the "video signal lost" footage just afterward, also had Ridley's roar briefly being heard.[4]
  • Metroid: Samus Returns Official Guide always refers to Ridley as "Proteus Ridley", even while describing the events of Zero Mission and the Space Pirates' raid on K-2L. While this suggests that he might have always been known as Proteus Ridley, this is not corroborated by any other canonical source.
  • In Greek mythology, Proteus is the name of the god of rivers and oceanic bodies of water, who was known for his adaptability and versatility. Therefore, the Proteus name for Ridley is appropriate as it reflects his ability to easily recover from his battle wounds.

Ridley slams Samus against the cliffside.

  • There are several instances in the Proteus Ridley battle that subtly or directly reference scenes and attacks from prior Metroid games:
    • The climax of Super Metroid, in which the mutated baby saves Samus by draining Mother Brain and transferring the energy to the former, is referenced when the baby drains Proteus Ridley and heals an injured Samus before he could kill her.
    • The confrontation with Ridley's adolescent clone in Metroid: Other M, in which he pins Samus to the ground until she is saved by Anthony Higgs, is played out in a similar fashion when Proteus Ridley pins down Samus until the baby's intervention.
    • On a similar note, the baby draining Proteus Ridley is similar to the Ridley clone's ultimate fate of being drained by the baby's own clone, a Queen Metroid. Unlike his clone, however, Proteus Ridley survives being drained. Similar to his clone, Proteus Ridley when being drained by the baby has his skin turn grey.
    • One of his attacks used by Proteus Ridley involves him grabbing Samus and slamming her into a wall, continuing the tradition of having Ridley possess a grab-attack in nearly all of his appearances since Super Metroid. Additionally, this particular attack is somewhat akin to his grab-and-grind attack from Other M and Adventure Mode: The Subspace Emissary.
    • The end cutscene of the battle with Meta Ridley in Metroid Prime 3: Corruption, in which she mounts his head and fires her Power Beam down his throat, is referenced whenever Samus successfully Melee Counters Proteus Ridley and proceeds to shoot directly into his mouth with a weapon of her choice.
    • Meta Ridley's defeat in Metroid Prime. Both Proteus Ridley and his Meta form flail at the end of their battles as a result of their cybernetic body short-circuiting with electricity.
    • Proteus Ridley's defeat shows him engulfed in a series of small explosions before he collapses, similar to Ridley's explosive defeat animation in Zero Mission.
  • Proteus Ridley's battle music is a remix of Vs. Meta Ridley, which is altered for each phase of the battle.
  • It is unknown why Proteus Ridley releases Aeion Orbs upon taking damage between the three phases of his battle, as Aeion only exists on SR388 and ZDR, and Ridley only recently landed on the planet.
  • Proteus Ridley is one of four characters to canonically survive a Metroid attack, the others being Mother Brain, Raven Beak and Samus Aran. The Federation Force soldiers can also survive Metroid attacks, although this only occurs in gameplay.
  • Proteus Ridley is the only Ridley form that is not acknowledged in his Palutena's Guidance conversation in Super Smash Bros. Ultimate.



  1. ^ Raquel Cornejo. ArtStation. Retrieved February 28, 2022.
  2. ^ Metroid: Samus Returns Official Guide
  3. ^ Yoshio Sakamoto: "In fact, it was MercurySteam's idea to use Ridley as the final boss. I knew it would be a surprise and that the fans would go crazy, so I gave my approval right away! I think it makes the story even more dramatic!" "The Metroids (2D) in which I have worked and the Metroid Prime are two different sagas; there is no direct link between their stories. When the Prime saga started, I agreed with its producers that we should try to preserve the timelines and a minimum level of consistency, but also to be free to create the games that we considered appropriate and avoid doing anything that would coerce the other."(translated from Spanish)
  4. ^