A rough draft. Comments welcome.
Aristocrats are minor aristocrats who have chosen the path of a warrior to make their way in the world.
Prime Requisite: STR and CHA.
Hit Dice: 1d6.
Maximum Level: 14.
Base XP: 2,000.
At first level, aristocrats hit an unarmored foe (AC 0) with an attack throw of 10+. They advance in attack throws and saving throws by two points every three levels of experience (i.e., as fast as fighters), and use the saving throws of fighters. They may fight with all melee and missile weapons, and may fight with a weapon in each hand, weapon and shield, or two-handed weapon. They can wear any kind of armor, and use shields. They may use any magic item usable by fighters.
Aristocrats start with the Command proficiency, plus one of Diplomacy, Intimidate, or Seduction.
When hiring people (employees, mercenaries, henchmen, contracting a sage, and so on), aristocrats treat the market class of the city as one better (Class I markets remain Class I).
At third level, aristocrats automatically gain a second choice from Diplomacy, Intimidate, and Seduction.
At fifth level, battlefield prowess inspires followers. Any henchmen and mercenaries hired by the aristocrat gain a +1 bonus to their morale score whenever the aristocrat personally leads them. This bonus stacks with any modifiers from the Charisma or proficiencies.
At seventh level, aristocrats become immune to all natural and magical fear effects.
At ninth level, aristocrats can build a castle in the same fashion as a fighter. In addition, the aristocrat gains the Leadership proficiency automatically.
At 11th level, aristocrats gain the last choice from Diplomacy, Intimidate, and Seduction.
The 13th level, aristocrats are masters of their domain: increase the Land Value of their personal domain by +1 while they rule it.
(EDITS: Swapped a bonus to saves with the Land Value increase at level 13.)