Quick history
Early life
Tsura is the daughter of a nomadic woman and an (at least to herself) unknown father. The tribe she belongs to is considered a minority. When she was 8 years old, her clan settled just outside a city to conduct business there. Tsura was then catched by the city guards and, legitimately or not, convicted for thievery. She and a few other members of her clan were imprisoned, the rest of the clan was chased off. After a month or so a prison riot broke out, and that gave Tsura the opportunity to escape. What she doesn't know however, even to this day, is that her mother was killed in the riot. (plot hook)
Puberty
Tsura fled into the city and found shelter in Elam Amparo's house. Elam Amparo is a simple but relatively wealthy man and member of another ethnic minority, but one that generally holds friendly relations with the diasporans. He took her in his household and supported and educated her until she was 15 years old.
During this time she met Hajna, a girl of roughly the same age. Hajna is an orphan or foundling or somesuch, adopted by Lord Epelanius, a local noble who isn't too influential in the national politics but he has some ties to people in higher positions. Tsura learned that Lord Epelanius was educating Hajna in the ways of the upper class and training her to be a courtesan. What Tsura didn't know was that Lord Epelanius was a nifty schemer who was also training Hajna to be a spy. In the meanwhile, Tsura herself was setting up a business of her own which consisted mainly of selling small stolen things.
When they were 15, Hajna received an invitation from admiral Dario Sintello to accompany him at the midwinter celebration at the Royal Palace. Hajna and Dario had met before on several occasions and were somewhat intimate with each other. Hajna, never being invited to a similar party before, was somewhat scared of going to that party and therefore she sent the admiral a letter, asking if she could take a friend with her, at least for the public part of the celebration. He responded and wrote that she could. Surprise, surprise, this friend was going to be Tsura.
(plot hook: Lord Epelanius finds out about this, for example because Dario discussed the matter with the party's host before responding to Hajna. And how coincidental: the host and Lord Epelanius could well be very good friends or even relatives! How did Epelanius respond to this? What are the consequences for Hajna? For admiral Dario? For Tsura?)
So Tsura and Hajna went to that party together, and the latter made sure Tsura and admiral Dario were properly introduced to each other. Despite Tsura being dressed appropriately to the celebration, Dario of course noticed her diasporan roots. And why not? There were enough tell-tales: her skin tone, her accent, her correct but somewhat off behaviour...
Hajna, being trained to see these sort of things, noticed that the admiral was rather interested in Tsura, but for the time being she could't figure out why. To her, Tsura was simply a diasporan girl who adopted the "civilised" way of living. (plot hook: why was he so much interested in the diasporan girl? Just general distrust? Does he have diasporan blood himself?)
Tsura didn't notice the admiral's interest in her but soon found out about it. During a certain part of the celebration, Tsura was able to take away a gilded chandler. She thought that nobody noticed. And nobody did. Except for the admiral... Later that evening he told Tsura what he saw, but that he wouldn't report her if she would leave immediately and come to his place the next week.
The training
Long story short: admiral Dario took Tsura in his household and trained her. At first, he refined her petty thief's skills such as pickpocketting, lockpicking, and concealing stolen things. He also taught her how to avoid to be caught in the act, how to remove evidence, how to know when someone is coming when she is somewhere where she shouldn't be, and how to get away unseen from a number of situations. Then he educated her in human anatomy, especially the weak points of any human body. He paid several of the Royal Army instructors to teach Tsura to utilise efficient hand-to-hand combat techniques. They focussed on specialised fields such as disarming and disabling people, and hitting victims on places where they would fall inconsious almost immediately, all as silently as possible. Then other instructors under Dario's command were employed to train Tsura in feinting, wielding small daggers, and in dodging attacks from others.
Training was strict, her schedule was tight, but in four years of hard working, Tsura had become an assassin in what seemed to be a large organisation. Admiral Dario, she called Nine of Spades now, whereas he called her Queen of Diamonds. Many of Tsura's trainers had similar names, like Ten of Hearts or Seven of Clubs. And not including Dario, she only knew these people by those names.
Rite of passage
When Tsura was 19, Nine of Spades said it was time for her rite of passage. Spies of the Royal Guard had identified someone who was weaving a complex web of intrigue behind the Queen's back. This someone was Duke Mallentone, the administrator of the province. Of course, he couldn't expose himself too much so he let his vassal sir Rabya do most of the work. As a result, Rabya was a central figure, like the spider in his web, and his "disappearance" would damage the Duke's conspiracy enough to make it harmless. It was Tsura's task to take him out.
She asked Nine of Spades to cause some uproar near sir Rabya's house when he wouldn't be at home. Enough, at least, to distract the guards and possibly even lure them out. So he did: Nine of Spades somehow made people actually fight in Rabya's front yard. Using the tumult Tsura slipped into the house and hid in Rabya's bedroom. She waited until he came home and enter his room, and slit his throat as soon as he had closed the door. Using a few of the techniques she had learned, she managed to get out of the house and away from the scene.
Ever after, Tsura has had a fairly normal life, in which she takes jobs in the city's numerous inns and taverns or plays her violin on markets, squares, and street corners. She meets up with diasporans a few times a year as they pass by. Then they do thinkgs like making music, dancing, singing, playing games, trading stuff, exchanging stories, eat and drink... Occasionally she "finds" interesting things in people's pockets. However, every now and then she receives an assignment from Nine of Spades but to this day she hasn't failed a single mission... yet.