Hit dice

It’s probably too late in the design process for this - and you may well have answered this question already - but here’s my twopenneth:
Given this blog post - The Demographics of Heroism - from 4th July, where you give attention to the idea of the uniqueness of heroic characters of high levels - is there enough distinction say between a 13th and 14th level fighter (+2 hp, 5% better saving throws / to attack) - or is there an argument for hit dice increasing beyond 9d8 all the way to 14d8 (for a fighter) - to increase the prestige / value of these upper levels?

A fighter in the level ranges you discuss probably has his power measured by realm size instead of HP pool. That being said, a level 13 fighter can only have level 12 retainers, while a level 14 fighter could have level 13 retainers. Also the wealth required to progress from 13 to 14 would probably have been invested in the fighter’s kingdom, thus the level 14 fighter would more than likely rule a slightly stronger kingdom than the level 13 fighter.
That is my take on it.

Wait, is it right that you can only have retainers who are lower level than you? I thought you could only recruit retainers who are lower level than you (and by high levels typically much lower). But take a level 13 king who has a level 12 Duke vassal/retainer. The Duke levels up to 13 (partly because his duchy is very large and profitable, partly because of building a set of giant castles, partly because of an adventure that the king did not go on). Does the now-level 13 Duke necessarily leave the service of the King? How does that affect concepts like vassalage and feudal relations?
Also, presumably PCs can be vassals of nobles who are the same level as them, right?

“you can only” and “you can not” are halmarks of Gygaxian actuarialism usually best left in the dustbin of AD&D. I suspect most GM’s will ignore those kind of “rules” and let the players make thier own decisions, in this case, decisions regarding numbers and compostion of courtiers, retainers and such.

A retainer (personal relationship) and a vassal (political relationship) are two seperate things.

@Marcus: Sure, but the rules seem to specify that your direct vassals = your retainers. From ACKS v.17 p. 116:
"Other domains in the realm are considered vassal domains, and must be assigned to a retainer, called a vassal, to manage. The retainer is responsible for collecting the revenue and paying the expenses of the vassal domain, and will pay 20% of the vassal domain’s monthly income to the adventurer.
“Since the number of retainers any character may employ is limited to between 1 and 7 (depending on his Charisma), very powerful characters may find that they have more domains under their control than can be managed even with all of their retainers. In this case, multiple vassal domains will be assigned to trusted retainers, who will themselves have to sub-assign vassal domains to their own retainers.”
The language of that section seems pretty clear at establishing that the assumption is that direct vassals are the same as your individual retainers, limited by your Charisma. If your retainers are limited to lower level than you, then so are your vassals (and so +1 are their vassals, etc.)
That also has the odd effect of implying that bottom level lords in a full Empire (Patricians in the Auran Empire lingo, “Lords” in the traditional more or less British naming system) would be no more than 7th level: Tarkaun/Emperor 14th->Exarch/King 13th->Prefect/Prince 12th->Palatine/Duke 11th->Legate/Earl 10th->Tribune/Marquis 9th-> Baron 8th->Patricians/Lords 7th. And of course, if a PC carves out a full empire at 12th level, which seems at least plausible to me, then their bottom level vassals would have to be no more than 5th level. To my mind, allowing vassals to level up to the same level as their (direct) liege lords without breaking the retainer/vassal relationship seems much more reasonable than enforcing a lockstep pattern up and down the line. Of course, there is an explicit statement that “A retainer automatically resigns if he reaches the same level of experience as the adventurer.” ACKS v.17, p. 86.
I think there’s some tension here that needs to be resolved. The realm system depends on having a cap, based on Cha, on number of direct vassals. But enforcing the standard retainer rules leads to problems at the bottom of the pyramid of noble ranks. Also, I assume that many 9th level PCs will start off as Patricians/Lords, just as overpowered Patricians/Lords who will try to quickly conquer their way up to the more level appropriate Tribune/Marquis, but the retainer rules makes any decision to swear fealty to, for example, an 8th level Baron, distinctly odd.
The easiest fix is just adding a statement that retainers who rule a domain or realm as vassals of their principal will not necessarily leave service upon reaching equal or higher level, although they may become less loyal.

“The easiest fix is just adding a statement that retainers who rule a domain or realm as vassals of their principal will not necessarily leave service upon reaching equal or higher level, although they may become less loyal.”
Agreed. The notion of disloyalty/plotting as a potential consequence of the retainer matching or eclipsing his liege is intriguing, with a capital I. That opens a lot of possibilities for Shakespearean plots. Gotta love those once stalwart henchmen who succumb to corruption or become disillusioned with their master and eventually rebel…

Looking at game of thrones, 4 things can happen.

  1. the liege lord and the vassal lord are quite different in power (starks and tullys): easy fealty.
  2. liege and vassal are same power (starks and baratheons) fealty by loyalty and friendship.
  3. liege and vassal are same power (lannisters and baratheons) uneasy fealty, until weakness is shown.
  4. liege and vassal are same power (stannis baratheon vs. Joffry baratheon) declare yourself a king of your own lands.

Another point to bring up is the idea behind granting your lands to your heirs. If your heir is not of a high enough level, or if his charisma is vastly different, your once peaceful and orderly lands could dissolve into anarchy as your original character’s retainers carve up their own lands into smaller kingdoms.

Ah, I see the confusion in the wording. I’m one of the players of the multi-year Auran campaign (hence the name) so I’ve got my own “remembered” version vs actual version issue to sort out.
For a party of adventurers running a realm, it’s easy to imagine the issue of most of them being the same level, but you still need a single figure as ruler. Just as the characters would decide (amicably or otherwise) who among the level 14s should be Tarkaun, with the rest giving fealty, the NPC retainer reaching level parity would get a similar option to continue as a vassal of their current lord, give their oaths further up the heirarchy (and perhaps claim a higher title), or perhaps declare the revolution and start his own realm.
I suspect, though it would definitely need to be clarified, that the intended outcome of an NPC retainer/vassal reaching level parity while running a vassal domain would be a loyalty throw modified by appropriate modifiers - length of service, treatment during said service (“hey, meat shield…”), etc.

An “easy fix” would be to drop the Charisma retriction on #'s altogether and let wealth and loyalty be the deciding factors in numbers of retainers, as in real life. The rule tieing # of hirelings to Charisma, to put it in historical context, was a late edition to the text of the Men and Magic by Gygax. The other designer (Dave Arneson) had a different view, preferring reputation to be the deciding factor in the ability to attract and hold retainers. (see Pegasus 1 pp 77,78 for example, or the AiF system). So the idea ofr dropping the Charisma binder on retainer #'s does have precedent in the roots of the game, for those who might car about such things.

Given this blog post - The Demographics of Heroism - from 4th July, where you give attention to the idea of the uniqueness of heroic characters of high levels - is there enough distinction say between a 13th and 14th level fighter (+2 hp, 5% better saving throws / to attack) - or is there an argument for hit dice increasing beyond 9d8 all the way to 14d8 (for a fighter) - to increase the prestige / value of these upper levels?
ALEX: While I can’t claim that capping HD at 9th is my invention, keeping it in the game is completely intentional. Keeping the characters to 9HD caps their Hit Points and therefore their relative combat power. It forces characters above 9th level, tackling harder challenges, to consider how to leverage castles, armies, spells, and treasure, rather than just being able “take it and dish it”.
suspect, though it would definitely need to be clarified, that the intended outcome of an NPC retainer/vassal reaching level parity while running a vassal domain would be a loyalty throw modified by appropriate modifiers - length of service, treatment during said service (“hey, meat shield…”), etc.
ALEX: I am going to adopt this as the rule. Something like a retainer being higher level is a penalty on the morale roll (-1 per level of difference).
An “easy fix” would be to drop the Charisma retriction on #'s altogether and let wealth and loyalty be the deciding factors in numbers of retainers, as in real life.
ALEX: Well… in real life, the number of retainers a person can have is definitely limited by that person’s innate talents (charisma, extroversion, personal energy). Each retainer (friend, loyal follower, etc) takes time and energy to manage. This is commonly studied by management theorists as “span of control”. The vast majority of people cannot effectively manage more than 3 to 6 direct reports. Likewise, psychologists have studied how many close friends a person can have and the number, again, tends to cap at around 6. People who think they have more close friends than that, or who think they are effectively managing lots of people, are usually fooling themselves. There’s a reason virtually ever organization chart and military structure has the same “pyramid” showing up over and over again. People naturally organize at scales something like 6/36/216 etc. i.e. squad/platoon/company.