I am looking for a word that would mean to oppose or overthrow the ruler in a monarch (the king or queen) led by another member of the high ranking officials. I considered rebellion but this would have a connotation of a faction of rebels. In my case, the word should rather denote a conspiracy, or an internal struggle of power within the governing authorities while being unknown to the rest of the people of the land.
Maximus led a mutiny against the ruler of the Inhumans
If a member of a royal family forcibly takes the throne from the rightful monarch, as though they had the superior right to that throne, then they are said to usurp the throne.
A usurper is often assisted by a cadre of supporters