The Ascendancy is ruled by a council of aristocratic Noble Houses, usually those who hold the greatest political power and influence. These aristocrats hark back to the austere and militaristic culture of the post-Terran Sol System in order to maintain their power. They operate spy networks within their own citizenry and reward those who uncover treason. Rebellion by the citizenry is crushed by overwhelming force when it is encountered, but the aristocrats constantly plot against each other and maneuver for advantage. Groups may be able to gain advantage with certain aspects of the government or with certain families, but this will almost certainly make them enemies of others.
The majority of the population are controlled by general propaganda, which reinforces the necessity of the Ascendancy's harsh rule, the benefits provided by the rigid social structure, and fear of dissenters, deviants, hedonists and rebels. The Ascendancy maintains the official stance that Terrans are the superior species within the galaxy, and client species are treated as useful second-class citizens - although they can advance and distinguish themselves within their individual fields, they cannot gain positions of rulership and join the aristocracy.
Player characters are extremely unlikely to start off as ruling members of Houses - Ascendancy Reputation is the metric of how close to the top your character happens to be, and characters with high Reputation are likely to become drawn into the brutal House politics. If you wish to start play as part of a House, then it would be appropriate to take a few ranks of Ascendancy Reputation with your starting skill points - gaining more ranks of Reputation might represent earning increasing clout within your own House, and there may be opportunities for advancement by…..other means. It is also possible for Terran characters with good Reputation to be offered the chance to be adopted into a House.