Monday, February 15, 2016

Monte-Carlo Measures of Monster Levels, Pt. 3

More observations and discoveries from coding and simulating the OD&D monster special abilities. See Part 1 for the table of Monte-Carlo measured monster levels (Equivalent Hit Dice, or EHD).

Undead and Energy Drain: One possible weakness of the simulated-combat model here is that it can't objectively weigh the value of long-term disabilities like energy drain, disease, and/or lycanthropy. In the scope of a single fight-to-the-death, these abilities make little difference. Of course, if a fighter of middle level can be assumed to have a magic weapon, then this cuts through all the undead defenses. So I was somewhat surprised to see wights measured at 1 EHD under their actual HD, and wraiths at just parity (arguing for no XP bonus, although higher types do start outstripping their base HD as a level of danger).

A few adjudications are necessary regarding OD&D energy drain, which might change your results: Does the target get a save? Does the drain reduce current hit points? To what XP level does the victim get reduced?

Personally, for some time I've been orbiting the zone of giving characters hit by undead a save to avoid the level-drain; however, the simulation here did not include that, and the EHD's for wights and wraiths still didn't evidence any boost for XP value. And yet I still like the texture of a saving throw; in the window where the player reaches for the die, rolls it, and watches for the result, it would seem like they get to "feel" the existential horror of the unknown in their gut, as opposed to the DM just announcing the loss as a done-deal-by-fiat. And it's consistent with giving a save for about every negative effect (like poison, paralysis, etc.) One remaining concern would be exactly what save to call for? I've been using the "Death" column (powers of undeath and all that), but it's the most generous save category, which feels a bit too soft, actually (almost 50% to save even at 1st level in the OD&D text).

Other decisions that seemed the most elegant while writing this in code: I had the energy-drain reduce maximum hit points, but not necessarily current hit points. Example: A 3rd-level fighter starts out at 15 hit points and gets hit by a wight; say the base 1d6 damage comes up "6", reducing current hit points to 9; and then the energy-drain kicks in, reducing level to 2, and maximum hit points proportionally to 10. So in many cases like this, the energy-drain may have no practical effect on current hit points or increased risk of actual death. This would be very different, and more dangerous, if the mechanic was to actually keep a record of damage taken and dynamically compute current hit points as maximum - damage when checked (but that doesn't resemble what I see most players doing at the table, so I didn't implement it that way).

Also, it seemed most elegant to just drop XP to 1 under the current level -- that is, the same mechanic used in the limit on gaining more than one level at once. That constitutes maximum generosity to the PC in question, and a single level loss is sure to be regained at the end of the given adventure when new XP is awarded (although still might be a lot of XP over the bridge, or multiple level losses a more lasting penalty). In the past I've used proportionally-rated XP drops (same relative location in XP as in the starting level), but I kind of like not having to pull out a calculator for that anymore. Alternatively, I think some rulesets specify dropping to the start of the prior level; the most punishing interpretation you could make.

Giant Hogs: Giant hogs are listed on the 3rd-level table for OD&D random monsters, and apparently in Gygax's Castle Greyhawk, the 6th level was nothing but a maze with "dozens" of giant hogs and lycanthropic leaders (link; and see below). Now, even the Monster Manual doesn't have an entry for "giant hog", but it does have "boar, wild", at 3+3 Hit Dice (same as the "3 dice" mentioned by Gygax regarding the Greyhawk level). This is a fairly weak opponent, only assessed at EHD 2 in the simulator (but at least it marginally belongs in the indicated table); note that the MM ability of fighting for a few rounds while in negative hit points is not something I could implement easily in the Arena code (in breaks the standard mechanic for hit points, and also breaks the Arena expectation that every fighter has an identifiable survivor/winner). On the other hand, if we were to use the 7 HD "giant boar" from the MM, this type would be much stronger, assessed at EHD 6, and so would belong at the upper end of the next table higher. So of the two, the Monster Manual's "boar, wild" has more evidence of being the better fit.

Lycanthropes: I only implemented the base type of lycanthrope, the Werewolf (you'll see that the same thing happened for Giants and Dragons, say). I was kind of surprised to see how underwhelming it is in practice. It's the only monster in the system assessed at two pips lower in EHD than its actual HD (i.e., EHD is only half HD). Assuming a fighter with a magic sword by this level, its defense is not relevant, and neither is the lycanthropy effect an increased risk to lose a given fight. If we assume no magic weapon for our fighters, then the EHD jumps from 2 to 4, the same as its HD (the Arena simulator does assume that fighters have a silver dagger to draw out in any case, but in that case their damage is halved from d8 to d4). Perhaps if we randomized from among the 4 types of lycanthropes in the book, this overall result would be a bit different (although even then HD are in a narrow range from 4 to 6, so likely not a huge difference).

Gargoyles: Similar to lycanthropes, and more critically, their main special ability is their defense in not being hit by normal weapons; and therefore the key to their measurement is at what level do we assume fighters will usually have a magic weapon? In my model that all fighters in the arena have the +1 sword, you see that the EHD turns up at 4, the same as its actual HD (and so: argues for no XP bonus). Of course, if your model/assumption is that fighters only get magic at some higher level, then the Gargoyle EHD will follow suit (at exactly the same number; the simple proof is left to the reader).


That's it for this week. Open questions: At what level would you assume that a fighter has a magic weapon (and so gets to hit high-level Undead, Lycanthropes, Gargoyles, etc.)? And how do you adjudicate the details of  Energy drain -- Saving throw? Hit points effect in combat? XP reduced to what level?


18 comments:

  1. If we're going strictly by the rules in Vol. III for dungeon treasure placement, then just doing some quick memo-pad calculations seems to indicate to me that a sizable group (say, 8-12 characters, counting henchmen or other NPC cohorts) might have to loot about 50 treasure rooms on dungeon level 1 to reach character level 2, and a like amount to reach character level 3 - assuming they're getting a sizable chunk of XP for slaying monsters as well, under the "100 per HD" schema. This is subject from some big outliers due to the lottery-like nature of gems and jewelry, of course, but what I'm interested in is the average case; I'm also rounding numbers off to make this simpler.

    Point is, by my reckoning of 100 treasure rooms to reach 3rd level, with a 5% chance of magic, that gives us 5 magic items. One-fifth of magic items are magic swords, and I'll ignore miscellaneous weapons for now because they're pretty rare and the rounding I've done has slightly inflated the number of magic items found already. So that's one magic sword for the group by 3rd level, probably another one by 4th level, and two more by 5th level.

    In a party of the sizes mentioned, you've probably got 1-2 PC fighters and 1-3 NPC fighters; assuming the PCs get the swords before the NPCs, there's a good chance for everyone to have a magic sword by 4th level - since the NPCs advance at half the rate, they reach 4th level when the PCs are reaching 5th level and a couple more swords have been found by then. This theory also matches up nicely with 4th level being Hero level, as well as with the fact that monsters with immunity to normal weapons start in the 3-5 HD range. It turns werewolves, gargoyles, and the wights into something of a "you must be this tall to ride" measuring stick.

    This also jives with where I intuitively thought that characters should have magic weapons; in the first campaign I DMed, 4th or 5th level was about when my players had a fair enough collection of magic items that most everyone had something.

    As for energy drain, now that I go back and reread the rules (both Vol. II and DMG) it's never really clear on the hit point loss question. It seems to be general consensus that it only reduces current hit points if the new maximum is lower than the current. This seems to be somewhat validated by the fact that AD&D allows for the possibility of being drained to 0th level without dying, being rendered a non-adventuring normie until and unless one receives a restoration or wish spell; this would be nigh-impossible under the deadlier interpretation of what it means to have your maximum hit points reduced.

    On the subject of XP, I started with 2nd Edition, so my default stance is based on what was printed there - the halfway point between the current level and the previous one.

    As for saving throws, I don't think any edition has given them at the time of the attack. I know that 3rd Edition gave a saving throw after 24 hours to avoid having the level loss become permanent, but that didn't help you until the end of the adventure. Then of course 4th Edition didn't include energy drain at all, while 5th Edition replaced it with hit point reduction (but no reduction in fighting capabilities) and granted an immediate saving throw to escape the effect altogether, and automatically recover after 24 hours in any case.

    So I guess what I'm saying is, there's very little precedent for it, but if it makes you and your players happy then go for it! Honestly, in its traditional form, I find that I and many other DMs tend to shy away from using it at all because it feels like such a screwjob - both to the player losing the powers that he's spent months earning, and to the rest of the party who are going to have to pick up the extra slack from an under-powered comrade until he catches up.

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    1. Nice analysis on the magic items! Glad that you agree about the hit point adjudication from energy drain. I do know that I'm off-book on the option for a saving throw, but to my mind, it makes a lot of stuff more consistent. That said, the numerical analysis done here assumes no saving throw as per convention.

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    2. I've always been a softy on energy drain - in my campaigns, it's been temporary, with a character able to regain 1 level each day with a successful save vs. death (using their current effective level, not their "true" level). I think in EGG's early campaigns, where they were playing multiple times a week, a level loss wasn't as significant as it has been in my campaigns, where we meet at most once a week. It still takes time to recover and leaves the character weaker for a portion of the adventure, but it doesn't undo weeks or months of progress in developing the character.

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    3. Hm, that's an interesting idea Stephen! I particularly like how it can be easily tailored to different levels on the "gritty vs. heroic" scale by increasing/decreasing the time between saves or the difficulty of the saves.

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    4. Stephen -- I agree there was probably a big texture difference in Gygax's early every-night games. I also think that explains the massive reduction in XP awards as of Sup-I.

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  2. Daniel Wakefield has done an admirable job with the rough-and-ready analysis of magic items, so I'll just agree with him on that question.

    My current thinking on energy drain is that it should have a save (this is because I currently don't consider a "hit" in combat to be necessarily a successful strike as such, and I do consider the energy drain effect to be one that is transmitted by touch - notably, the ghost's ability to age the target is not a touch based one for me, and I would not give it a save as a result; the save is an expression of the target taking hit point "damage" while avoiding being touched). I will stick with the AD&D (1E) specification that XP are reduced to halfway between the levels. I'm also pretty set on the effect only reducing max hit points, not current amounts (unless the max is reduced below current hit points).

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    1. I agree that the more I think about it, the more a saving throw for energy drain really feels "right" to me. Also it feels like I could be a little more liberal with those undead and not have to mete them out quite so carefully.

      The past few days I'm really more troubled by the energy drain not reducing current hit points. Like: it should _hurt_ by default; and not create a situation where you go from damaged to damage-free. But I hate the technique of recording damage instead of current hit points for this mechanic. On a computer it's not too bad a calculation to invert that, but manually at a table in combat it would be a bit of a drag.

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    2. For what it's worth, I ran the simulation of the more strict ruling on hit points (however much max hit points are reduced from level loss, reduce current hit points the same), and overall danger level is not very much effected, e.g., no EHD effect for wights, and just +1 EHD for wraiths and spectres. Either way it's not a huge difference; but what I just jotted down for my margin rule is to allow a save, give max XP in the reduced lower level, but apply the strict interpretation of the reduced hit points.

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  3. Re: energy drain, why not roll one hit die for the drained character and subtract that as extra damage caused by the drain? Level loss is the longer-term consequence (whether you make it permanent or not) and the damage reflects the immediate (but more quickly recuperated) pain of being touched by Death.

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    1. Yeah, I think that's sort of the way I'm going except like this: however much max hit points is reduced from the level loss, reduce current hit points the same. I don't know why I was making it out to be more complicated than that.

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    2. Delta, I believe what Seth is suggesting is the precisely that - that when you get a level drained, roll a hit die; you lose that many maximum hit points permanently AND take that much extra damage. This, of course, hinges on whether you're using the original hit dice or the variable hit dice introduced in Greyhawk. It works perfectly with the linear hit die growth from Greyhawk, but doesn't quite work out with original hit dice - at least not without some modifications - because not all levels are worth a full die of hit points.

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    3. Oh, good point, I agree with that then. The only modification is that in practice I don't roll, I take a proportional amount off the hit points. (e.g., 3rd-level fighter with 15 hp automatically drops to 10 hp on energy drain; and using Sup-I hit dice).

      AD&D DMG recommends tracking each level's rolls for hit points so you can back them out, but I find that to be egregiously complicated record-keeping. On the other hand, you wouldn't want a case where maybe you roll 8 hp on level-up and only lose 1 hp on level-down a few times. So I think the proportional loss is both pretty easy and the middle ground for possible gain/loss differential.

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    4. Why not swapping the damage and drain? So, first drain the victim affecting max hp (and possibly the current hp if max hp < current hp) and only then apply the damage from the hit.

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    5. That sort of does it halfway, but doesn't account for previously existing damage. Example: Fighter has max 12 hp, down to 8 hp from prior fight. Now gets hit by wight: energy drain drops max hp to 8 (apparently making him undamaged), and new damage roll of 4 takes him to 4 hp. So somehow he's got 8 max hp, and he's taken 8 hp damage total, but he's still up.

      It's a potential ruling, but the ordering seems weird to me.

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  4. Well, then I would suggest to drop max hp but keep damage taken. So, in your example max hp drops to 8, but total damage was also 8 and he would now be at 0 hp.

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    1. Right, and with that ruling the order doesn't matter.

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  5. Ah, I misread your post. I see now that this is exactly what you already mentioned.
    Sorry

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    1. Cool, great minds think alike. :-)

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