Emerald Sustrai

Emerald Sustrai is an antagonist in RWBY. She is an associate of Cinder Fall and a partner of Mercury Black.

Appearance
Emerald is a thin female with medium-brown skin and dark-red eyes. Her hair is a light, mint-green cut with a straight fringe and bangs, as well as two long locks on each side, in the back. She wears two bronze-colored rings on her middle fingers as well as a pair of high-heeled shoes.

Originally, her attire consisted of an intricate, exotic-looking white top and olive undershirt, on the back of which is her personal emblem. This emblem is in the shape of a cut gem, most likely referring to her name. This was intended to be accompanied by white shorts, decorated with what appears to be a gold coin-plated belt, with four gold chains draping around her back from two of the coins and what seems to be a green loincloth.

She also wore a gold, three-ring armband on her left arm and a string of gold beads near the same wrist. As of Volume 2, her outfit has changed somewhat. Her top has thinned, her undershirt is now shallow-cut, and her armband and beads no longer seem to be made from gold.

She now also wears white pants and brown chaps that end at her calves and an overlong belt, twice-wrapped, where she keeps her weapons as well as a single pouch. Her hair is also noticeably fuller and longer and her irises are wider.

Haven Uniform
Later, she is also seen wearing the Haven Academy uniform, a more conservative dark gray outfit with a long-sleeved collared top and white armband.

Flashback
In "Beginning of the End", Emerald was younger and had her hair tied into a pony tail.

Her previous attire was a short exotic olive top, and she wore her signature chaps and belt. Beneath her chaps she wore dark green pants, and plain dark brown flat shoes. She also wore white half-gloves.

Personality
Emerald initially appears to be affable and disarmingly friendly; however, this belies a darker side of her character. On the whole, she seems to be genuinely outgoing and quick-witted, if a little short-fused. She can also act a little childish or petty, such as when she stuck her tongue out at Roman Torchwick after she stole his lighter to mock him.

In "Best Day Ever", when she talks to Tukson about books, she seems to be knowledgeable about books and enjoys reading, as she lists off many titles. She also likes Vale, complimenting the city for its "tall buildings and diverse culture".

She has a tendency to maintain a pretense of friendliness amongst people in order to gain their trust. This is shown on multiple occasions in "Best Day Ever", where she pretends to be friendly to the Shopkeep in order to catch him off guard and steal his wallet. Later in the same episode, she puts on a friendly act around Tukson before threatening and killing him. Another example is in "Extracurricular"; where she mostly ignores Ruby Rose until she looks directly at her, when Emerald off-handedly smiles and then rolls her eyes when Ruby looks away. In the episode "Round One", she states that she dislikes Team RWBY for their cheery and positive attitude, regardless of her acting as their friend for the time being.

Emerald shows a strong sense of loyalty, specifically to Cinder, whom she appears incredibly eager to please. Accordingly, she is willing to take the initiative to impress her, such as tracking down Tukson and killing him. When Cinder rebukes her for killing Tukson, she defers to Cinder's judgement, quickly apologizing.

Judging from the nonchalant way she talked about killing Tukson, she appears to have no qualms about killing, even lightheartedly joking about it afterwards with Mercury. However, another side of her is seen in "Battle of Beacon", where she seems to be overwhelmed and disheartened at the sheer scale of the destruction and violence taking place, calling it "almost sad".

Abilities and Powers


Emerald's weapons can take two main forms - primarily, they act as a pair of dual-wielded pistols, but they can also be converted into a pair of short kusarigama. Emerald seems to be quite adept with her weapons, demonstrating skilled swordsmanship and marksmanship, using both of her weapon forms to fend off Grimm single-handedly in the episode "Breach". She later demonstrated the ability to ensnare opponents in her chains and reel them in, even from a great distance.

Emerald is stated by Mercury to be a master thief, and she has proven that she is adept at pickpocketing, with one victim being Roman Torchwick, stealing his lighter to show him that she was a capable thief after he mocked her. As seen in her fight with Coco Adel, her stealth abilities allow her to move silently and attack from an enemy's blind spot.

Emerald is also shown to have impressive reflexes, allowing her to avoid Tukson lunging at her and dodge Coco's rapid gunfire with ease.

Semblance


Emerald's supposed semblance appears to be perception manipulation - the ability to modify the sensory information in a person's head while their brain is processing it. In short she can make one, or multiple individuals simultaneously, see and hear things that aren't necessarily there.

This power was pivotal in Cinder Falls's plot to rig the Vytal Festival and incite anger and distrust towards Beacon Academy. After Yang Xiao Long's victory against Mercury in the singles battle, she made Yang see an illusion of Mercury getting up and attacking her, prompting Yang to counterattack by supposedly breaking his leg. However in reality, Mercury hadn't attacked at all, making Yang's counter seem, to everybody watching, like an unprovoked attack in cold blooded spite. The resulting anger, outcry, shock and distrust from the masses of watchers stirred the Grimm wandering Mountain Glenn, as the Goliaths turned their attention to Vale.

Before this her power had been used to lead Amber into a trap to steal her maiden powers, where Emerald made Amber see a crying child on the road, prompting the maiden to lower her guard; and also in her and Mercury's fight against Coco and Yatsuhashi Daichi of Team CFVY. She used her power to hide herself and Mercury from the eyes of her opponents. After Emerald pulled Coco into the canopy section of the arena, Emerald tricked her again by making her see Yatsuhashi come up to her, seemingly victorious, only to have his knock out announced and broadcasted in the other section of the ring. Emerald then seized the opportunity to attack a bewildered Coco and knock her out as well, winning the doubles match.

Emerald's semblance was also the main reason Cinder first scouted her, having witnessed Emerald use her power to trick a jewel merchant, in order to steal one of his rings - the merchant just smiled at her, as she took the ring right before his eyes.

Her power is however shown to have its limits. Whilst she seems capable of controlling a single mind, controlling any more than that seems to tax her own head severely. After playing an illusion on two medics who came to pick up Mercury, so they wouldn't see his mechanical legs, she was shown to have a considerable headache. It is unknown what the consequences of manipulating any more would do to her mind.

Trivia

 * Both Emerald and Mercury lacked 3D models in Volume 1, and were simply shown as 2D image sprites instead.
 * In the episode "Best Day Ever", Emerald is established by her actions and Mercury's own words as a "master thief". Later, Roman refers to Emerald as a "street rat", a term used to describe the title character of Aladdin. It could suggest the basis of Emerald's character, as well as her name making allusion to the phrase "diamond in the rough", which is spoken in the Disney adaptation of the tale.
 * Emerald is a real life gemstone, that is most often found in green colors.
 * Sustrai (capitalized) is the Basque word for "thief" while sustrai (not capitalized) means "roots" or "undercurrent". It may also come from the Spanish word "sustraer" which means "to steal" or "rob".
 * Emerald's appearance greatly resembles that of Cleopatra, who was supposedly cursed by an emerald.