Velisca is the legate Veramus trusts with the work he cannot give the army. She built the emperor's intelligence and she runs it, and when the reports out of the Slaver's Coast grew too consistent to keep ignoring, she is the one he sent south under a false name to find out how far Slavewatch had rotted. The garrison there knows an investigator passed through. They do not know it was her, and they do not know she is still listening.
What she carried back was worse than corruption, which Veramus had already assumed. Tribune Volso takes bribes. That is the least of it. He has made himself the hinge the whole western trade turns on, selling passage to escaping slaves with one hand and selling the slavers warning of the inspections with the other, and the empire cannot be rid of him because every officer competent enough to replace him dies of mountain fever inside his first year. Velisca set this out for the emperor in plain words. Then she watched him understand that there was nothing he could do with it.
I gave him the truth and he thanked me for it. That is the part nobody believes. The danger was never that I would lie to him. — Velisca, recorded by an unknown hand
This is what makes her the most dangerous person at the court and the most loyal at the same time. She holds the proof that the trade Gorath's wealth rests on is being quietly looted, that the emperor knows, and that he cannot stop it. Said aloud in the wrong room, with an election coming, those three facts end him. Velisca has not said them. She has served Veramus a long time and she serves him still. But loyalty is a thing she chooses again every morning, and she is far too good at her work not to know exactly what the secret would fetch from the men who want his throne.