Emerald Sustrai

Emerald Sustrai is an associate of Cinder Fall and a partner of Mercury Black.

Appearance
Emerald is a thin female with dark 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. She wears two bronze-colored rings on her middle fingers as well as high-heeled shoes.

Originally, her attire consisted of an intricate, exotic-looking white top and olive undershirt along with 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 seem to no longer 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.

Later, she is also seen wearing a more conservative dark gray outfit with a long-sleeved collared top and white armband, possibly as part of a uniform or disguise.

Personality
Based only on the sneak peek of Mercury's fight with Pyrrha, which shows Emerald observing on the sidelines along with Ruby, she seems mostly aloof while exhibiting a pretense of politeness. This is shown when she mostly ignores Ruby until she looks directly at her, to which Emerald off-handedly smiles and subsequently rolls her eyes when Ruby looks away.

According to the first episode of volume two, when she talks to Tukson about books, she seems to be knowledgable about books and enjoy reading, as she lists off many book titles. She also likes the city of Vale, complimenting the city for its "tall buildings and diverse culture." This may indicate that she has tastes for architecture and multiculturalism in cities. Also, she is willing to take some initiative, along with Mercury, to accomplish missions, such as tracking down Tukson. She can also be a bit childish, such as when she stuck her tongue out at Roman after she stole his lighter to mock him.

Judging from the nonchalant way she talked about killing Tukson, she appears to have no problems with killing, even light-heartedly joking about it afterwards with Mercury. Although, she is still loyal to Cinder, assuring her that an incident won't happen again.

Abilities
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.

Emerald is shown to have impressive reflexes, being able to avoid Tukson lunging at her.

Despite only being seen briefly in the Volume 2 Opening, Emerald seems to be skilled in using her weapons when fending off Weiss.

Trivia

 * Both Emerald and Mercury lacked 3D models in Volume One, 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 mean Emerald's name was inspired by the saying "diamond in the rough."
 * Sustrai (capitalized) is the Basque word for "thief" while sustrai (not capitalized) means "roots" or "undercurrent." It may also comes from the Spanish word "sustraer" which means "to steal" or "rob".