A Client represents the interests of a group of citizens of the Empire. Every Imperial Citizen has a right to representation by a Client. A block of clients is represented by a Patron. A Client can post a petition to their Patron.
The relationship between a Client and Patron was hierarchical with mutual obligations. A Patron possesses greater wealth, power, or prestige that enables them to help or do favors for the client. In return the clients would offer their services to patrons when needed. It's similar to Ancient Rome.