Ber is a pretty new nation, and a foreign power coming in and pushing for a change of leadership is probably not going to end well. Also, as a new nation it doesn't have a well-designed formal system for replacing the Bruse; it'd either be a coup where the new ruler needed a lot more support than Shantus, or the legislators (and I don't recall if we ever stated that Ber has a Congress, or Parliament, or something else) would need to create a system.
A lot of the nation's unity is in the shared identity of throwing off the dragon tyrants, and the idea that they're actually a civilized nation. So the second option (creating a formal system) would be most likely to work.
Maybe it could be framed as, "In light of the recent assassination attempt against Bruse Shantus, we realize our laws of succession are not comprehensive. It would have led to a crisis among people vying for control, right as our nation needed to band together to rebuke a dragon tyrant's attempt to subjugate us. Therefore, we propose these formalized lines of succession, taking inspiration from Risur and Danor."
Then you'd set it up so that the Bruse has to have a successor named, and if there is no named successor when the Bruse dies or becomes incapacitated, a temporary Bruse (called the Bolder) is appointed by the Congress. Likewise, if the Bruse goes for a year without naming a successor, the Congress can name a successor for him. Once a successor is named, if the Bruse wants to name someone else, the change would only take effect after a year, to help people plan long-term.
Shantus would be irked at this, because he's a paranoid a-hole who doesn't want someone offing him to take his place. So he'd probably name Corta Nariz, thinking it would keep her father from trying to perform a coup against him. Then it would be up to Cavallo de Guerra to turn public opinion against Shantus so much that the Congress could pass a new law giving them the ability to expel the current Bruse.
It would be messy, like any regime change tends to be, . . . and honestly it probably wouldn't finish playing out before something else in the campaign changes how things go.
