How to deal with them.
In Crusader Kings 2, outright assassinating a troublesome relative often ends badly. The assassination may fail, leaving you even worse off. Even if it succeeds, all your other relatives (as well as unrelated vassals) get antsy about your tendency towards murder and become that much harder to govern.
What is a lot easier, however, is imprisoning people. A well-placed relative with claims on your own titles often gets a bit uppity when they feel they aren’t getting the respect they deserve. In turn, this tends to make them do things that violate either the law or just good form. While outright killing the person is very difficult and even fighting them in open battle tends to be problematic, one can generally imprison a proven transgressor with little blow-back.
Once in prison, your options open up. If you’re short of money, you can just use a little bit of extortion and release them in suitably short order in exchange for gold. However, if removing that person for good would substantially improve your situation, you’ll not want to see them released. You could just keep them imprisoned indefinitely and wait for nature to take its course or you could hasten things along. Imprisonment can vary in severity from something more like house arrest, to a standard lockup, to keeping the prisoner in such horrible circumstances that an untimely death becomes quite likely. Setting up a conspiracy to actively snuff out a prisoner under your control (while making it look like an accident) is also much easier than going after a free man.
In my Crusader Kings games, I’ve tried most of these options. It usually takes me considerable longer than I expect it to, but I’ve had the occasional success.
Thus a sense of deja vu as I wrap up the second book in the Accursed Kings series, The Strangled Queen. Depending on what version of events you want to accept, one or more of the Crusader Kings options come to life. Officially Queen Marguerite, wife of Louis X, died in prison from a cold as a result of the poor conditions within her prison. She had been sent away after having been accused and convicted of adultery in the the the Tour de Nesle Affair. Of course it is just possible, isn’t it, that someone who wanted Marguerite out of the way could have hastened that death along with a little foul play? The sooner she was gone for good, the better, particularly once there was a replacement queen waiting in the bullpen.
What I’m coming to appreciate about the series is the author’s fascination with seemingly small decisions that have nation-moving consequences. Something done for temporary political advantage, or even just because the mood strikes, might have the consequence of plunging France into one hundred years of war. It both makes an interesting story and an interesting way to foreshadow the narrative.
I also have noticed (and appreciate) the style of the book where the author is telling the 700-year-old story, but speaking to the reader in the present day (well, 1950s in the case, but close enough). It’s a small touch that adds to the readability of this well-written and well-translated series.