Ok, I gotta get in on this one! :-) I've been reading your stuff for a while now and I've not had the courage to post, but this sounds like the plot to one of the DnD games I was in and it was great, so anyhow!
The person that came in had the same story that many of the others did. A tale of woe where they'd been convinced the King's rules were why the person lived in poverty and pain. Why they came to the palace suffering of an infection that could easily be treated, and cleared up in less than a month, with proper medical care and treatment. This person is highly intelligent, skilled, and knew to listen before they struck, but also knew how to play dumb. But more than that, this person had their own spies, their own little network, and once they accepted the deal, learned the truth behind their old Lord's lies, knew just the perfect way to expose their former Lord in a way that they, and the other conspirators, were dragged into the daylight. The entire kingdom knowing exactly what they did and who they really were.
[AN: Well, shit, now I have to think of something that will work]
A great man once said, Murder is for the unimaginative. If you kill them, two things happen - first, they don't learn anything. Second, you end up playing into everything they said you were in the first place.
There had to be another way.
The sixth knife came with intense eyes and the kind of thoughtful mien that made sensible mortals quake in their shoes. She was the one Knife that didn't come with a weapon, but interviewed every single one of the extant five Knives and then made an appointment to join them.
She was the only one to investigate everything. The King asked her why. "Because the Lords keep blaming you, and those who go to right wrongs become your guards. There has to be a reason. The reason is... the lords are masters of horseshit."