Yes really. You are quoting from the henchmen rules. I don't have my DMG here, but if you go to the pages which have the tables for determining NPC personalities etc (a bunch of d8, d10 and in one case at least d24 rolls) you will see what I am talking about.Not really.
The bottom line is that trying to construct a coherent treatment of NPCs relative to PCs from the 1st ed DMG is a fruitless task.
NPC mercenaries and sailors are in many cases statted up as fighters, but unable to gain levels. Nothing is said about how to generate their stats. (Do these fighters who are unable to level nevertheless get a share of the XP for fights in which they participate, which then dissipates into the aether? I think the implication is probably yes, but the rules don't actually say).
NPC henchmen are presumably generated and gain levels as PCs (subject to the half-experience rule). This is consistent with my impression of how single player but mutiple character play worked in the early days (eg Gygax GMing Kuntz's PC + henchmen).
NPC assassins, monks, thieves and the like, who are attracted as followers by high level PCs, presumably gain levels normally - there are references to this under the relevant PHB class entries, but no indication is given as to whether or not they are burdened by the half XP rule.
Fighter followers are a tricky thing. The DMG tables suggest that some of the followers attracted are standard 0-level mercenaries, but some are levelled fighters. Whether those levelled fighters are able to gain further levels (as are monk, thief and assassin followers) or whether they are fixed in level (as are the mercenary officers discussed in the hireling rules) is left unstated.
Exactly which NPCs the rules I referred to upthread - ie the rules which set variant stat minimums and/or stat modifier - are meant to apply to is not stated. Presumably not henchmen, but it is all left as an exercise for the reader.
Even 0-level humans aren't treated consistently across the rules. The Monster Manual entries tend to imply that hit points for a 0-level human are 1d6, but the DMG gives a varying range, with women having fewer hit points than men and both sexes having their hit point range depend upon how sedentary their occupation is. And according to the DMG mercenary hirelings have hit points of 1d4+3 (4 to 7), not 1d6.
And then we have sages (which have been mentioned upthread) who (I think) have their own rules for stat generation, have (I think) 8d4 hit points, and have access to a mix of clerical and magic-user spells depending on their fields of knowledge, but get spell slots at a rate that don't correspond to any PC class spell tables (they're closer to the way that 1st ed AD&D allocates spells to dragons).
And none of this tackles the issue of how all the above-mentioned rules are meant to fit into the design of NPC random encounters discussed in Appendix C, some of which are with adventuring parties, some with the soldiers of NPC landholders, etc.
What should we infer from all this? Well, one fairly clear conclusion seems to be that Gygax et al didn't feel especially constrained by any pre-given ruleset in statting up NPCs; that they sometime were prepared to use PC class mechanics, or elements thereof, as a device for statting up NPCs, but were happy to treat the relationship between stat minimums, class abilities, earning of XP and level progression, etc as all pretty flexible; and that trying to state in some definitive sense what it means, mechanically, to be an NPC in 1st ed AD&D is - as I said at the outset of this post - a fruitless task.
Apparently I have. I can't give you the page, because my book isn't ready to hand, but as I said earlier in this post it's in the same section of the book as that setting out the many tables for NPC personality etc.Actually, other than addressing some alternatives for adjusting ability scores on p.11, 1e has no special rules for NPCS at all, outside of rules specific to hirelings, mercenaries, etc. Unless you found some section of rules of which I am unaware.
I can't remember everything that's there, but it says that NPC fighers, clerics, thieves and wizards be given a +2 to their prime stat (which presumably has been rolled on 3d6, although I think this is not expressly stated), preserves the 17 minimum CHA for NPC paladins but I think reduces some of the other stat requirements, and reduces the stat requirements for druids and ranges (for PCs these are 12 WIs + 15 CHA, and (I think) 13/13/14/14 STR/INT/WIS/CON for rangers - for NPCs these are lessened, maybe 13 or 14 CHA for druids? maybe 12/12/13/13 for rangers? I don't have it all memorised anymore.)
Yes. And what happens if a player wants to pick up an NPC mercenary officer as a PC. Can that NPC suddenly start gaining levels? The rules don't say, although presumably the intended answer to the question would be Yes.Let's not forget how often a henchman or hireling might become a PC when a player's character dies or becomes incapacitated.