Tuesday, 10 May 2011

Hit Dice Quirks: 4+4 or 5?

In some old-school d20 rulesets, such as Labyrinth Lord or its source Basic D&D game, hit points added to a monster's hit dice are just a "bump" up to the next hit die, so a creature with 4+4 dice attacks as a 5 hit die creature. Others, such as Swords & Wizardry or 2nd Edition AD&D, base their attacks on straight hit dice, so a creature with 4+4 dice attacks as a 4 hit die creature. Lamentations/WFRP's core rulebook still doesn't say how monsters get attack bonuses ... Anyway, my game uses the S&W convention, easier to remember.

With this system, and d8 as your hit die, each plus of 4 1/2 ends up averaging out to another hit die, and a 9+9 HD creature has the exact same average number as an 11 HD creature (49.5); just a tighter spread (18 to 81 vs. to 8 to 88). But, the 11HD creature is better at attacking and saving throws.

What I wonder is how much monster design takes this feature into account. There's a certain inertia when it comes to messing around with the ogre's 4+1 or the troll's 6+6, arbitrary figures seared into a generation's brains from adolescence.  After a while, hit dice codes seemed to be put out there for sheer novelty value, jumping the wereshark in Monster Manual 2 with stuff like 13+39 (the arcanadaemon), 2+8 (the tri-flower frond) or 7 plus, um, 3d4 (the annis). Keep in mind that each +3 hp counts as an extra hit die when attacking, by 1st Edition AD&D rules. Math is hard!

Or is that seven, plus three, minus twelve? Or 10-19 HD?
Anyway, back to straight-up hit dice combat tables. Why shouldn't the hill giant - long on endurance, short on skill - fight with 6+10 instead of 8+1 hit dice? Is a S&W cockatrice with 5 HD really better at attacking than a near-equivalent werewolf with 4+4? What about more fragile creatures with ample skill and fortune, like sprites or bird-men - shouldn't they have minuses (4-2 hit dice)?

OK, I find that it's hard to mentally budge those iconic numbers for the classic monsters. But maybe it's a thought when we turn to designing new ones.


  1. Which resolution are you leaning towards after writing this? Still with S&W on this topic?

  2. I don't think I noticed the 7 + 3-12 stuff before... that's crazy!

    Here's how I convert from Swords & Wizardry to Weird West which has separate Fighting and Stamina stats.

  3. @Timeshadows: Yes, getting hit bonuses from base HD still makes the most sense to me and allows for messing with HD versus +HP in a way that means something, within monster design.

    @Stuart: Right, your conversion makes explicit how fighting skill can vary independently from stamina (average HP).

  4. Thanks.
    --I (too) think it works.

    There was a recent blog post somewhere that took an expanded Monster HD and Special Ability table from a Dragon Mag. issue and I've been looking for it ever since.
    --I even recruited Stuart to help find it, but alas, no cookie.

    Any ideas which blog it may have been?
    --Anyone? Please? :D

  5. Delta had a breakdown once of the OD&D encounter tables by hit dice and abilities, is that it?

  6. Here is an image of the table:


    I still don't know who posted it.

  7. I had never thought of that before, but it really does work that way, doesn’t it?

    I’m going to have to keep this in mind as I design my own monsters.

  8. LotFP Weird Fantasy monsters have a hit bonus equal to their Hit Dice; it's in the Referee rules if I remember correctly.