Sial was a very successful solitary thief.
In 1479 DR, Kal'dir finally found her and offered her an opportunity to meet the new Xanathar. In front of the beholder, Sial challenged its authority, proclaiming herself the best burglar of the city and accusing the Xanathar's agents of being inefficient. Impressed, the Xanathar offered Sial a position as a lieutenant in the Xanathar's Guild and she accepted.
In time, she also became the guild's spymaster.
Sial supervised all the guild's activities involving thieving and burglary. She also directed the spy network of the guild, often discovering things that Kal'dir, Quid, or Draak believed they'd kept secret.
Sial had no stable home, normally wandering all of the city's districts.