Marisol originally came from El Salvador. During an invasion, Hector murdered her parents and she also believed him to have murdered her brother, Gabriel, as well.
Marisol appears in the episode Entanglement. Martin Bohm meets with Marisol on Transit Bus 22 after Wember Hsu steals his laptop and runs onto the bus with it, but fights off Martin and escapes. He sits beside Marisol and apologizes, but notices she is holding a pistol by his side and she orders him to shut up for the next six blocks so she can escape despite his pleas that he has to get to a meeting. Soon, a big man named Hector gets on the bus and Martin believes him to be Marisol's accomplice but she refuses to answer his questions. Finally, Martin threatens to talk if she doesn't start answering soon and she explains her backstory with the gentleman. The bus is soon halted by a Middle Eastern man crossing the street (Aakif), causing her to drop the gun. Martin and Hector soon flee but Marisol corners them in an alley. Hector flees after Marisol gets distracted by the fireworks from the Chinese parade Wember organized, and Marisol pursues only to be hit by an arriving vehicle. Martin learns from Hector that the children were smuggled and not executed, and that the boy awaiting a bone marrow transplant at the hospital is Marisol's brother. Martin successfully talks Marisol into being a donor for her brother. At the end of the episode, she visits Gabriel in the hospital and the two smile at each other.
(To be added)