I even know why they went to war with the queen, the threat to their income from tariffs and tolls.
But what I don't know is who they are, since any number of possible characters could object, violently, to the loss of income. Nobles, of course, given their prerogatives -- both financial and military -- but that's not a character trait.
I don't even know how many there are. Fortunately, thus far, it looks like villainous infighting is not going to be a major factor, so I can keep it down. (One major reason why this character ended up queen was that major nobles feared taking the crown when they had so many rivals It will help here.)