Mercury Black

"My dad always said... "if you need to know a city, ask the rats.""

- Mercury Black

Mercury Black is an antagonist in the world of RWBY. He is an associate of Cinder Fall and partner of Emerald Sustrai.

Appearance
In Mercury's first appearance in Black and White, he was shown to be a pale, well-built man with gray eyes and, while draped in shadow, seemingly purple hair (revealed to actually be gray in the credits of the same episode), partially slicked back while unkempt at the front. He also wears a gray and black two-tone partial-zip jacket, that covers his upper body.

Mercury's appearance did not change much in Volume 2, though his hair and eyes are now a silvery-gray. A not-so-noticeable change is his style of belt. In his first appearance, he appears to be wearing two belts, one crossing the other. He now wears a single notched belt with what appears to be a sash or bandana draped over it.

He has prosthetic legs, which attach part-way up his thighs. These legs are usually hidden, due to him always wearing pants and a pair of shoes. His armor hides what appear to be oddly-shaped scars on the outer sides and backs of both of his arms.

Background
Mercury lived in the mountains with his father, Marcus Black, who was an assassin and implied heavy drinker. One night, he fought against his father and killed him. Cinder Fall and Emerald Sustrai saw their fight from afar and were hoping to recruit his father for their cause. However, due to Marcus' death, Cinder asked Mercury if he took after his father. He joined Cinder's cause and has been traveling with them since.

The trio first appealed to Adam Taurus of the White Fang, proposing an alliance. However, they were turned down. But, the three were able to ambush and sap Amber of half her Maiden abilities, before retreating due to the timely intervention of Qrow Branwen.

They were able to leverage Adam into their alliance after killing many of the members in his camp. Adam was forced to accept the offer, where the three would provide him with resources, such as Dust and funding, or face death if he refused.

In the post-credits scene for Volume 1, Mercury and Emerald are seen accompanying Cinder Fall to a meeting with Roman Torchwick.

Volume 2
In Best Day Ever, after Emerald asks for directions to a local shop, Mercury appears from around a corner and jokes that he knew she was lost. Emerald pulls out a stolen wallet and offers him the money if he shuts up, but he refuses in favor of toying with her. They arrive at the store owned by Tukson and Emerald asks him if he has certain books. When Emerald begins to reveal why they are really there, Mercury dims the windows of the shop and kills Tukson when he tries to attack them.

When Mercury returns to Roman's hideout with Emerald, Mercury informs Roman that they were cleaning up his mess. Cinder soon arrives and Mercury confirms that they had killed Tukson before he had the chance to flee. When Roman tries to explain to Cinder why he hadn't done the job himself yet because of how busy he is stealing Dust, Mercury compares him to any punk with a gun and ski mask. He then leaves the warehouse with Cinder and Emerald.

In Welcome to Beacon, Mercury arrives at Beacon with Emerald and Cinder, posing as students from Haven Academy. The three bump into Ruby Rose, where Mercury informs her that they got turned around looking for their building. Ruby then tells them the direction of their building and the trio continue on their way as Ruby welcomes them to Beacon.

In Extracurricular, Mercury is seen again watching Pyrrha Nikos fight with Team CRDL in a class based training fight. Once Pyrrha finishes with the former, Mercury challenges her to a sparring match. Glynda Goodwitch briefly protests this, but Pyrrha gives her approval and the match begins.

The fight is tense, with both parties probing for weaknesses and studying their opponent's skills. Pyrrha briefly uses her Semblance of polarity to manipulate Mercury's boots, throwing him off-balance. Midway through the brief but intense match, Mercury abruptly forfeits, stating that Pyrrha, a world-renowned fighter, is completely out of his league. After the match, he briefly converses with Emerald and enthuses about how much fun he finds learning. He is later seen discussing Pyrrha's semblance and skills with Emerald and Cinder in their dorm rooms, conveying his findings from their match.

In Dance Dance Infiltration, Mercury is seen at the Beacon Dance dancing with Emerald while talking to Cinder through a headpiece at certain points as she infiltrates the Cross Continental Transmit Tower. After Cinder arrives at the dance, having successfully completed her mission, Mercury dances with her and asks how her night was, to which she responds that it was much more exciting than expected.

In Breach, Mercury appears alongside Emerald and Cinder during the Grimm attack on Vale, with the latter silently nodding to the two to attack, and help in taking out the Grimm attacking humans. Shortly after the fight, Merucry, Emerald and Cinder are overlooking the city of Vale from a rooftop. When Cinder remarks on the day being successful, Mercury adds that with them having lost so much Faunus in the caves, the White Fang won't listen to them anymore. At that moment, Adam Taurus appears and reassures them that they will listen to him.

Volume 3
In Round One, Mercury is first seen observing different boots at a stand in the fairgrounds. After Emerald is done conversing with Team RWBY, she turns to Mercury, and he asks if she got the information. She tells him Weiss and Yang will be fighting in the second round. He is later seen eating a big bowl of popcorn while spectating the match between Team JNPR and Team BRNZ along with Emerald and Cinder.

In It's Brawl in the Family, he witnesses the fight between Qrow Branwen and Winter Schnee. As soon as he recognizes Qrow, he seems genuinely worried and runs off to report to Cinder.

In Lessons Learned, he and Emerald are later faced off with Coco Adel and Yatsuhashi Daichi of Team CFVY in the double match due to Cinder rigging the matches up. He and Emerald easily win the match.

In Fall, he is elected to represent his faction in the finals round of the tournament, facing off against Yang Xiao Long in the first match. While the two are appear to be evenly matched in the beginning, Mercury unleashed a storm of rounds at her. Just as he walks away, brushing his clothes off in confidence of his "victory", Yang rebounds from his attack and proceeds to unleash a beatdown that costs him the match.

However, he is involved in an elaborate ruse where Yang is tricked into thinking Mercury still planned on attacking her despite his lack of Aura. This causes Yang to fracture his leg, thinking that she was responding in self-defense, which allows him to frame Yang for bad sportsmanship and assault as the cameras reveal that he merely walked towards his opponent before she damaged his knee. Emerald rushes to his side as he clutches his leg and cries out in pain. However, his legs are prosthetics, and he can repair them himself.

In Beginning of the End, he is evacuated by Cinder and Neopolitan in an Air Bus to their secret warehouse where he hides away for a while so that nobody knows his leg is fine. Cinder's plan carries on with him in hiding.

In Destiny, at the beginning of the next tournament match, Ruby finds him in the stadium with fully healed legs. He notes that the next matchup, Pyrrha versus Penny, will be chaotic due to Pyrrha's polarity and Penny's metal body. Mercury then assumes a fighting stance, preparing to attack an unarmed Ruby.

In PvP, after Penny's destruction he leaves Ruby to grieve without further harming her.

In Battle of Beacon, Mercury is seen with Cinder and Emerald, standing on a rooftop as he is filming the scene on a Scroll with glee. As Cinder instructs him to focus on the infected Atlesian Knight-200s, he willingly obeys before being interrupted by the Grimm Dragon's arrival, which Mercury also focuses on.

Personality
Mercury is shown to be rather care-free and jokes around when in the company of Emerald, whom he makes an effort to annoy. He seems to opt for excitement and action; he dislikes books without pictures and tells Emerald that he finds the city boring. However, when it comes to matters at hand, Mercury drops this, focusing himself on the mission.

During battle, Mercury displays a sense of seriousness and levelheadedness. Based on his fight with Pyrrha Nikos, he appears to test and gauge his opponent before fully committing to an attack, implying that he has a strategic mind. His cunning is later shown once more during his match against Coco Adel and Yatsuhashi Daichi in Lessons Learned, where he takes advantage of the savanna biome to hide before lauching a surprise attack on Coco. He also uses the geyser biome to his advantage, using it to create an opening on Yatsuhashi and defeat him.

Judging from the nonchalant way he talks about killing Tukson, Mercury appears to have no qualms about killing, even light-heartedly joking about it afterwards with Emerald. Although subtle, he also speaks in a derogatory fashion about Tukson even after having murdered him in cold blood.

Fighting
Mercury is shown to be a very acrobatic and agile fighter who relies on quickly overpowering his opponent with complex kicks that imply a near-mastery of martial arts that resemble Tae-Kwon-Do. He's also capable of a break-dancing style, similar to Capoeira and making use of Muay Thai as well. His experience and skill with his leg-based fighting style is aggressive and effective enough to drive even a fighter of high caliber and great combat experience like Pyrrha Nikos, considered to be the strongest first-year student at Beacon Academy, into a defensive position.

Despite his focus on kicks, Mercury also uses his hands to grapple, block, or redirect enemy attacks. In his fight with Coco and Yatsuhashi, he grabbed them both and twisted them into an easier position for his kicks, and even stretched out Coco's arm, allowing him to kick her in the head. During his battle with Yang, he showed deft skill by using his arms to weather Yang's barrage of punches, which Yang is known to be very skilled at throwing. His skill in utilizing his arms were shown in the same fight as he occasionally punched at Yang before following suit with a barrage of kicks.

Mercury is also known to be an observant, tactical and analytical, as he notices and deduces the capabilities and limits of Pyrrha's Polarity Semblance after she used it once during their brief fight. His observation skills were later demonstrated once more when he was able to track down Ruby's movements while she used her Semblance, a feature the combined efforts of Team JNPR were unable to stop during their brief fight against Team RWBY.

Mercury reveals the impressive extent of his skill in the doubles round of the Vytal Festival, dominating both Coco and Yatsuhashi single-handed with his impressive feats of speed and strength, being capable of evading Coco's barrage of bullets, which possessed a noticeable spread and were fired at a rapid pace, and counter-attacking from the air swiftly. His speed is later demonstrated once more when he was able to track and intercept Ruby's movements even when she was using her Speed Semblance in a last resort effort to escape from him.

Due to his fighting style, Mercury relies on his swift and quick reflexes to counter and block his opponents attacks, as demonstrated at first during his fight with Yatsuhashi, in which he used certain kicks to alter the course of Yatsuhashi's sword strikes, or blocked them altogether with his boots. His quick reflexes are later seen once more when he is occasionally seen altering the course of Yang's punches by raising her fists with his impressive footwork and kicking underneath or around her attacks to avoid being hit.

Weapons
Mercury's weapon of choice is a set of boots equipped with a firing mechanism built into them similar to Ember Celica. Similar to Yang's usage of her Ember Celica, Mercury is capable of firing explosive rounds from his boots whenever he kicks for moderate to long-range combat. Most of the time he's seen firing his boots are usually mid-handspring, also known as a kip/kick-up or when maneuvering his body in a manner similar to break-dancing, more specifically "Thomas flairs" and "airflares", and is able to fluently translate from his aggressive Tae-Kwon-Do-like kicking style strikes to this Capoeira style. He is also seen using it in a more traditional manner with frontal or side kicks.

Mercury can also control the rounds through Dust use. During his tournament fight, he gathered multiple rounds that spun around him in a manner similar to that of a cyclone surrounding him before the rounds were later unleashed in a devastating flurry. He also possesses, at the very least, capable marksmanship skills, being able to fire his Dust rounds efficiently despite the barrels being located near the soles of his boots, as shown when he fired a round at Yang before using his cyclone technique during their fight and when he shot Ruby's Scroll out of her hands during their confrontation.

He can also use the boots to jump in midair by bringing his legs together and firing his boots simultaneously, boosting him forward and allowing him to achieve temporary flight.

Prosthetic Legs
Mercury has a pair of robotic legs which he acquired at some currently unknown point in time. His prosthetics make-up over most of his leg, including a portion of his thigh and everything below the knee. He usually keeps them concealed under his pants. These robotic legs appear to give him enhanced performance in battle, such as being able to withstand blasts of fire without taking damage. He can also easily repair "injuries" to his legs that would otherwise put a normal human out of commission or require medical attention.

His prosthetics are also quite durable, being able to withstand significant attacks that would otherwise severely reduce Mercury's Aura. His prosthetics have so far protected Mercury against a nearly point-black firestorm, a storm of crystallized leaves, a massive strike from Yatsuhashi's sword, and a direct point-blank blast from one of Yang's Ember Celica shells.

His kick-based fighting style, as well as his choice of weapon, are likely intended to take advantage of his prosthetic legs. His prosthetics are capable of firing blasts of air, which he makes great use of in combat.

Trivia

 * Mercury alludes to the Roman god Mercury, whose Greek equivalent is Hermes.
 * Mercury's symbol, a winged boot, as well as his weapons, may be an allusion to the winged sandals of the mythological Mercury.
 * His colors are black, gray, and silver, likely to give off the tones of the element mercury.
 * Both Mercury and Emerald lacked 3D models in Volume One, using 2D still image sprites instead.
 * Mercury's last name, Black, was originally suggested by his previous voice actor J.J. Castillo.