|Miltia and Melanie vs. Yang||"Yellow" Trailer||Lost|
Miltia and Melanie Malachite were born to gang leader and criminal, Lil' Miss Malachite who operated her organization in Lower Mistral, growing up with their mother and the organization she took over, Spider, becoming members of it. At some point, their father was seemingly killed by Lil' Miss, but they hold no grudges against their mother.
Chapter Four: Cheat
During a gang war between Spider and a rival gang, The Mouse and Parrot, 13-year old Miltia and Melanie are placed in the protective custody of Roman Torchwick, who at the time was Lil' Miss' right hand man, for the duration of a week. Without much else to do other than watch television and talk, the three found themselves incredibly bored at the hideout they were staying at. During this time, Roman would use his journal to plan schemes and heists, which Melanie would take note of. Melanie points out his plans and ambitions are destined to fail as they’re incredibly short-sighted and thuggish, much to the rising criminal's annoyance. She and Miltia suggest he should instead find a partner (preferably with a useful Semblance), and turn his focus to Dust – as taking a large share of the resource which the world revolves around would guarantee that he profits from it.
As Roman thinks through their suggestion, his Scroll buzzes. Chameleon, an operative of Spider and Roman's partner, contacts him with information that Jack Plum, a former rival of Lil’ Miss who they failed to spy on and were nearly killed as a result, had returned to Mistral. Chameleon tips off his location, The Mouse and Parrot's headquarters, letting Roman know she’d contacted him about it first and that Lil’ Miss would be second – giving him a head start to correct past mistakes. With this information and the knowledge about a mysterious basement at their hideout, Roman recruits the twins to help him.
Unbeknownst to the Malachite Twins, Roman plans on taking advantage to betray Spider and sell the two out to join the Parrot gang. Hiding Miltia as insurance, Roman and Melanie wait outside the hideout, where they meet a contact from the rival gang, Badger. Badger asks the 22-year old if Melanie is Roman’s new girlfriend, which Torchwick makes no effort to refute and disgusts Melanie.
At the base, Roman meets with the leader of Parrot, Paul Parrot, and claims he wants to work with the man. He offers the twins as a ransom, with promise that Lil’ Miss would pay him well to return them. Instead, Paul offers Roman his life - as he had already taken Miltia, who had snuck into the mysterious basement. Reading into Roman's personality and realizing that he cares for the twins, the gangster allows him inside to amuse himself. There, Roman finds Miltia cornered by a Capybara, large rat-like Grimm, imported from Menagerie to deal with the Mouse and Parrot organization’s problems. Roman manages to shake the Grimm off her, and in doing so, lets it loose in the city of Mistral, killing Badger in the process. He and the twins leave the basement to find themselves surrounded by Spider, who'd arrive to the twins' rescue. This experience sours the relationship between Roman and the twins.
Chapter Eleven: Trivial Pursuit
After Roman betrays Spider, Lil' Miss sends her daughters to Lady Browning's Preparatory Academy For Girls in Vale to work with Beatrix Browning in order to both assassinate Roman and prepare for Spider's plan. At the Academy, the two quickly become extremely popular, using their popularity to pull pranks on less popular students like Trivia Vanille. One night, the two sneak out of the prep school and arrange an assassination on Roman alongside Honey Wine, a Spider associate. The two attack Roman, quickly subduing him.
Chapter Twelve: Double Trouble
However, their assassination attempt is thwarted when a young girl aids Roman, casting an illusion of him to throw off the Spiders and allow him to escape.
Chapter Thirteen: New Girl
The next day, the twins pull another prank on Trivia Vanille. When Trivia learns that the Academy is actually apart of Spider and is host to a secret training program to create spies and assassins, she realizes the Malachite Twins are under this program. She joins the program, and from this point on her life in the Academy takes a turn for the better. Trivia and the Malachites grow closer and become friends with one another.
Chapter Fifteen: Fight and Flight
After watching a sparring session between Trivia and a Huntress who worked as a combat instructor, Manda Rin, the twins invite Trivia to join them in clubbing, revealing they're assigned to kill Roman much like Trivia was. Trivia, who had been secretly going by Neo, realizes she has to get to Roman first to save his life, and declines their invitation in order to look for him.
Chapter Eighteen: Panopti-Con
Later, when Neo realizes that Roman is on the verge of being kidnapped and learns of Spider's plan, she runs into the Malachite Twins who had caught her trespassing The Room, which she wasn't allowed in at the girl's school. Worried she could not fight both the twins, Neo flees.
After this, Lady Browning's Preparatory Academy For Girls' connection to Spider is exposed, thus rendering it inactive. With Spider's plan having failed and the organization retreating to Mistral, it is unknown where the twins stand with their mother now. The exact circumstances are unknown, but eventually, the twins began working under Junior Xiong as his personal bodyguards in his club.
Miltia and Melanie are first seen at the bar next to Junior, but he sends them away when Yang Xiao Long takes a seat next to him. After Yang assaults Junior and defeats his henchmen, Miltia and Melanie confront Yang themselves and hold their own against Yang's fighting style, even knocking her down.
However, Melanie is knocked back soon after and Miltia is forced to fight Yang on her own. She is unable to compete with Yang's speed without her sister and is soon sent flying through a large glass column.
Miltia is seen briefly in "Painting the Town..." She is sitting by the entrance of the club, next to her sister, seemingly observing Yang talking to Junior. When Neptune Vasilias tries to talk with them both, they tilt their heads dismissively and walk away.
Following the Fall of Beacon, Miltia likely abandoned the club after Grimm entered the city.