I don't do regrets. (c)
Zan'xi is a pureblood Sith Lord, born on Dromund Kaas and trained in Korriban Academy during the fall of her family and death of her parents, who lost in one of the power games inside Sith Order. She cut ties with her family (since she was and stays a real loyalist at heart and scheming of her clan involved many dubious tactics) and avoided the purge, continuing to study in the Academy and moving to make a career in military after that.
During a decade of serving the Empire in Sphere of Military Offence she managed to avoid major political intrigues, getting to high enough position and earning reputation of competent commander and respected loner, who prefers battling a real outside enemy to scheming. She is used both to leading black ops missions and assuming command in major warzones, and doesn't find military routine and personnel beneath her - which gave her a lot of experience, good knowledge of military strategies and tactics, and bag of mercenary survival and fighting tricks collected along the way.
Her hidden passion is good old lightsaber dueling: she treats it as art and appreciates a good "dance" with master of the blade. Zan'xi is also not alien to matters of ancient mysteries and lore, descending from the esteemed line of scholars, though she rarely shows that.
Seen as a stiff pureblood at first sight and military brute at second, she is fine with upholding to that image - believing that it's always good to have a tactical advantage.