The society of the Compact of Arvum follows a very hierarchical pattern with the wearer of the crown at the very top and descending based on one's status within the nobility. When designing a character, players are given a great deal of leeway in choosing where socially their characters might fall. The top two social ranks are restricted, as the characters that inhabit those positions are already defined with clear genealogy and orders of succession, but players are permitted (and encouraged) to make characters right beneath that, and most of the powerful ducal houses are kept intentionally vague and unnamed to better allow players freedom to design their own if they so choose.
Social Rank 1: The King/Queen of the Compact of Arvum, who ostensibly holds the fealty of every person under his writ from the high lords that rule each great house to the lowest serf. Only foreign rulers are considered social equals to the crown, and those are largely unknown to the average member of the Compact. Most commoners have never heard of Cardia or the Empire west of the Eventide Vast, or the kingdoms of Eurus. Even most educated peers of the realm and scholars only have heard the barest of whispers of those far lands, so it's customary to think of the ruler as uncontested.
Short mode of address: 'His/her/your majesty'. Excruciatingly Formal Mode: 'His/her imperial majesty, King/Queen <Name> <House> of the Compact, the Royal Crown of Arvum, Defender of the Realm'.
Social Rank 2: Directly underneath the crown are shared by those in direct succession, which includes the immediate family of the ruler and the royal spouse, as well the five high lords that rule each of the five great houses of Arvum. Traditionally, the King or Queen of the Compact has also been one of the five high lords that rule a great house, but not always. The sovereign has at times appointed another of their family (typically their heir) to the head of their own house in their stead, so the monarch can focus on the Compact as a whole rather than the individual control of their family.
Short mode of address: 'His/her/your grace' for the high lords that control the five great houses, 'His/her/your highness' for the royal family. Painfully Formal Mode: 'His/Her grace, Prince/Princess/Duke/Duchess <Name> <Family>, the Prince/Princess/Duke/Duchess of <Home City/Fortress>' ie 'Her grace, Grand Duchess Esera Velenosa, the Archduchess of Lenosia' or 'His grace, Prince Donrai Thrax, the Prince of Maelstrom'. as Lenosia and Maelstrom are the home cities of House Velenosa and House Thrax respectively. Addressing the royal family: Given the courtesy titles of Prince or Princess, and are referred to as 'a prince of <House>'. The ennobled are typically referred to as lord/lady to distinguish them from the true born, and those that are married to the High Lord/High Lady are referred to as "His/Her highness, Prince/Princess-Consort Name, Prince/Princess of Family", Or short-form: His/Her Highness.
Social Rank 3: This tier contains the rulers of the most powerful vassal houses to the great houses (typically dukes/duchesses), the family of the high lords that rule the five great houses, and the the most influential pillars of society just below the high lords (such as the Dominus of the Faith). The families of the great houses within the line of succession are given the courtesy title of prince/princess if they are true born, and lord/lady if ennobled or adopted and outside the line of succession.
Short mode of address: 'His/her/your highness' for families of high lords, 'my lord/lady' for any peer of the realm is widely considered acceptable, the more formal forms below high lords and their families are quite rare. Pompously formal form: 'His/her/your highness, Prince/princess <name> <house>, a prince/princess of <House>'. Thus while the current high lord of House Thrax is 'the Prince of Maelstrom', one of his male children would be called, 'a prince of Thrax'. For vassal lords, 'His/her lordship/ladyship, Duke/Duchess <name> <house>, the Duke/Duchess of <Holding>.'
Social Rank 4: Contains the family of ducal houses, all given the courtesy title of lord/lady, and the heads of significant marcher lord houses whose titles have a degree of variation including Marquis/Marquessa, Marquess, Margraves, or just Counts of the March in the Lyceum. Same modes of address as above.
Social Rank 5: Contains the families of Marquis/Marquessa/Marcher lord ranks and also heads of Count/Countess rank houses. Accorded all the same respect and dignity of higher peers of the realm, with the same modes of address.
Social Rank 6: Contains the families of nobles of Count/Countess rank as well as all Barons/Baronesses and their families, the lowest of the peerage but still accorded all due dignity. A handful of commoners can be treated as peers and reach this rank, typically high rank members of the Compact military or holders of high offices and granted courtesy titles of lord/lady.
Social Rank 7: Contains the highest of commoners who are often treated with the same dignity and respect as nobles. This includes courtiers, knights, priests, lawyers, high officials, military officers, and guild leaders. This can also include the wealthiest and most successful of commoners, such as merchant princes of prized artisans. As commoners, typically any titles they possess for formal modes of address are tied to their occupations, such as the owner of the courtier Whisper House being referred to by her job title of 'Radiant'.
Social Rank 8: The vast majority of commoner labor. Serfs, peasants, apprentices to guilds, most men-at-arms, and all the commons and smallfolk that are often treated as the great unwashed by their extremely distant lords. Lords of houses rule by fiat over their domains and can live and die by the whim of their liege without often any legal recourse. In Arx, the crownsworn might hope for some better protections, but it is still largely left to the discretion of whatever lord or member of the Iron Guard that crosses their path. As a rule, higher lords very seldom interfere in the affairs of their vassal lords who are dealing with their own servants.
Social Rank 9: Thralls of House Thrax, the rabble in the Lower Boroughs, the riff-raff that gentle company scorn. Not necessarily criminals, but these are considered the cast-offs of society. Shady characters can be found here.
Social Rank 10: Enemies of the Compact. Primarily these are the Abandoned, those that actively refuse to recognize the writ of the Crown and fight against the Compact of Arvum and try to prey off the lands of the five great houses. Generally not suitable for player characters.