Rigel and Tonilia grew up together in Markarth, but went different paths because Rigel wanted to look after her aging father (monetarily) and the Thieves Guild was losing power. She became a bandit, but found nothing but frustration in large part because of the incompetence of her underlings. If she could be convinced that the Guild's fortunes are changing, she seems like someone who would be in the mood for a chance of scenery...and some more adept company. Her voice is as tough and forceful as she is.