Background
Santhe was born on the ocean world of Pantolomin, just before the outbreak of the Clone Wars. Her family enrolled her into the Pantomin School of Performing Arts, where she had gotten her education in the latest acting and computer tech courses, becoming a fair actor but a much better slicer, able to combine scenes of real time and generated characters with ease.
Months after her 22nd birthday, while at school she'd heard through the grapevine that Alderaan had been destroyed through a "astronautical anomaly". She'd managed to get her hands on the footage and with her technical prowess had seen through the Empires deception. A week later she'd had all her things stowed on a freighter and escaped to the outer rim to link up with a Rebel cell.
After a few weeks of basic training she had become disillusioned with the idea that the cell that she was with would be able to stand up to the might of the Empire. She cut her ties with that group and made her way from the planet, knowing that could never go home unless she wanted to be arrested and charged with treason, and had to find her own way in the galaxy.
Motivation
Santhe despises what the Empire had become, after having grown up in the early days of the empires rise, she realized after the destruction of Alderaan that they can never be trusted. Her short stint with the Rebellion has made her think that they're just the Empire re-branded. She since has come to the idea that she should stash together enough credits to buy herself a place far from either.