Blog-Crosstalk-Attack: "WTF does 1HD+1 mean?!" (seen at Dispatches from Kickassistan)

I was about to do something completely different when I read +Adam Muszkiewicz's great post about Stupid DM Tricks over at his amazing blog Dispatches from Kickassistan. Was then about to write a comment, did some research (yeah, I do that at times ...), started writing and thought after a few sentences "Dang, that's a post of it's own!". So here I'm, hijacking Adam's post. I hope he doesn't mind ...

Crosstalk (biology): "In electronics, crosstalk is any phenomenon by which a signal transmitted on one circuit or channel of a transmission system creates an undesired effect in another circuit or channel. Crosstalk is usually caused by undesired capacitive, inductive, or conductive coupling from one circuit, part of a circuit, or channel, to another." [Wikipedia]

This post is only about a small part of Adams post and will answer a question he already answered as he needed it for his post. Anyway, I immediately thought there should be more to it. Well, first things first, here is the question:

"WTF does 1HD+1 mean?!"

And his answer to that is (or at least the conclusion):

"Thus, unless we start statting up monsters as 1+3 HD or other nonsense, then the "+1" really means "it's really a 1 HD creature, but it fights like a 2 HD creature;" in other words, it's 1 HD tough, but 2 HD dangerous. Now that orc and the hobgoblin are significantly, interestingly mechanically different and we know what the fuck HD 1+1 means!"

He is right, of course. But that's not the main reason for the existence of this phenomenon. It's more like a byproduct, actually. In my opinion anyway. But let me elaborate on this a bit. My point of reference will be the D&D Rules Cyclopedia since I'm quite familiar with it and my first thought after reading this had been something like "But doesn't the D&D RC state that ...". And here we go. There'll also be some stupid math ...

It's not about using monsters, but about improvising them!

Let's start with the section "Changing Monsters" in Chapter 14: Monsters (D&D RC, p. 214). It is, in my humble opinion, on e of the best sections in the book as it's one of the few occasions where the RC lifts its skirt and gives the reader a good look unto the underlying assumptions of its system. The gist of it (about tinkering with the size/experience of a monster, p. 214 and 215):

If smaller:

• Much smaller than normal -3
• Smaller than normal -2
• Slightly smaller than normal -1 

If larger:

• Slightly larger than normal + 1
• Larger than normal (2-3 x size) + 2
• Much larger than normal (4+ X size) + 3

Choose whichever modifier you think is most appropriate for this type of monster. For example, an ogre that is Much Larger Than Normal would take the + 3 modifier.
These modifiers are similar to ability modifiers for characters. They are used in the following manner: 

• Hit points: Add the modifier as points per Hit Die.*
• Attack rolls: Add the modifier to the roll.
• Damage: Add the modifier per die of damage.*
• Saves: Subtract the modifier from the roll.
• Armor: Subtract the modifier from the AC.

* There should always be a minimum of 1 point per die. 

To calculate the XP value of different size monsters, take the total number of bonus hitpoints and divide by 5, rounding up fractions; add the result to the base HD total of the monster. This is the number of Hit Dice to be used when calculating XP value.
For example, a normal-sized gorgon would have: 

AC 2; HD 8*; THACO 12; Dmg 2d6; Save F8 

The largest variety of common gorgon would have: 

AC -1; HD 8 + 24*; THACO 9; Dmg 2d6 + 6; Save F8 + 3; XP Value: As 13 HD 

Tribal Leaders: Some creatures that live in tribes have hereditary leaders who gain the title by birth. The larger size of these leaders can be reinforced through the generations; most will have modifiers of + 3 based on the guidelines above.

There is so much to use right here, it's uncanny. For one it answers the question if the "+x" is added to the sum of the HD or to every one of them. It's added to the sum, BUT when changing the size of a critter the modifier is multiplied by the number of HD before it's added to the sum (in other words, added to each die!). So a Larger Than Normal Goblin  would end up with:

AC 4; HD 1+1; Dmg Weapon +2; Save Normal Man +2; XP Value: as 3 HD (35 xp)

That's tougher than an orc or even as a hobgoblin. More like a small ogre, actually. The idea is that the HD of a monster entry is merely the average of that monster, but the bigger/smaller variants don't just have more or less HD, they have more or less substance. Look at the hydra above: 8HD+24! That's 24 hp granted just for being big as f*ck. So the "+" gives indications how meaty an individual version of a monster is, with the modifier and the HD being the limit (AND the additional note, that well bred variants don't need to be bigger to be formidable specimen, see the Tribal Leader part above).

Use leader and size together and you'll end up with the fat
Goblin King from The Hobbit [by Alan Lee, source] 

There is also that little sentence that "these modifiers are similar to ability modifiers for characters". Let that sink in for a while. In a sense it makes the whole xHD+y scheme the worlds smallest character sheet (without using classes): xHD = Level of a creature and +y as indication for ability score bonuses beyond the average and as used above (resulting in bonuses to saves, damage, et cetera). That does a lot with very little.

And lastly: this is where you begin when you build your own monsters. How mighty is it with HD used as comparison to character levels and how well is the particular specimen developed (the "+y" used as comparison to ability modifiers). Add the "*"-system for special abilities from page 128 of the RC (every * stands for a special ability a monster has and adds to the overall xp of a creature) to that and you got a very good short-hand with an easy way to calculate xp to improvise your own monsters on the fly. I mean, come on, that's kind of nifty, right?

So yeah, what Adam said, but ...

As far as the "+/-1" for the average monster goes, it's just an indicator if those creatures usually are a bit weaker or stronger than the average character counterpart (again HD vs. Level), which means a direct impact on that modifier described above. That way the ominous 1 HD-1 goblin, for instance, results in a somewhat weaker creature than other level/HD 1 characters/monsters would get. Look at the example above. While that Larger Than Normal goblin sure is impressive, he'd have been much more so without the "-1" tweaking the result. It's subtle, but it's there.

Of course it's also important for the xp one gets for killing such a beast and it's good to have that little distinction, as it allows for a more detailed xp distribution. But there's so much more (often unused?) potential to the whole concept.

So I hope I was able to add to the discussion with this little post of mine. Anyway, nothing of this is my doing, it's all the Rules Cyclopedia. I just thought it's very well worth sharing, as some might not be aware of the rules quoted above and where the possibilities are. Now I want to play that game again ... Gotta love the Rules Cyclopedia :)