D&D 5E Surf's D&D 5e Monster Analysis

[Quickleaf]

[MENTION=84774]surfarcher[/MENTION]

I've been following your blog recently, and really appreciate your fine toothed comb analysis trying to understand how monsters are built in 5e.

One thing that perplexes me is Hit Dice. Specifically, how many Hit Dice a monster gets and the relationship between Hit Dice and CR. Any inkling how this works yet?

For example, take a CR 1 monster. According to your chart, it should have 9d4 (22.5) hit point if it is Tiny, 7d6 (24.5) if Small, 5d8 (36) if Medium, 3d10 (16.5) if Large, 3d12 (19.5) if Huge, and theoretically 2d20 (21) if Gargantuan. Which seems to completely undermine the idea that bigger things have more hit points.

Clearly there is not a perfect correlation between Hit Dice and CR, given the discpancy between old and young dragons (little HD difference but big CR difference) and "glass cannon" monsters with really potent abilities having fewer HD to compensate. There are dials one can turn, for example, one for HD and one for Special Abilities. Both effect CR.

What I'm trying to figure out is...

(a) What is the Hit Dice baseline for each CR? I think this is one number for each CR, irrespective of a creature's size. For example, 4 HD might be the CR 1 baseline, with a medium creature getting 4d8, a large creature 4d10, etc. I choose "4" as my example because it is the average party size in 5e (the standard range is 3-5 characters), and a CR 1 creature is supposed to be a moderate challenge for an average size level 1 party.

(b) What "standards of exchange" between Hit Dice and Special Abilities (or other factors) can be deduced from the existing monsters? For example, if I have a CR 1 monster and I want to make it have less hit points and more Special Abilities while keeping its CR the same, what is a 2 HD (for example) drop worth roughly? An area attack ability? Blindsight? A defensive trait? A Pack Attack trait? A higher AC?

Anyhow, I'm looking for answers as I read thru the monsters with an eye toward making connections, not in anywhere as scientific a method, but rather on what I believe is the more fuzzy "art" of monster design.

 

[the Jester]

What I'm trying to figure out is...

(a) What is the Hit Dice baseline for each CR? I think this is one number for each CR, irrespective of a creature's size. For example, 4 HD might be the CR 1 baseline, with a medium creature getting 4d8, a large creature 4d10, etc. I choose "4" as my example because it is the average party size in 5e (the standard range is 3-5 characters), and a CR 1 creature is supposed to be a moderate challenge for an average size level 1 party.

I am not the surfing one, but I suspect that, rather than "target HD", 5e monster design has "target hps" and doesn't really care how you get there. If the target is about 50 hp, you could have a big, burly giant (huge size for d12s, CON 16 for +3 per die) and only need 5 or 6 hit dice; or you could have a feeble monkey-like creature (small size for d6x, CON 8 for -1 per die) and need 20 HD. Since proficiency is based on CR rather than HD, the game doesn't care. (Shades of 4e monster design, basing hp on level!)

 

[Quickleaf]

I am not the surfing one, but I suspect that, rather than "target HD", 5e monster design has "target hps" and doesn't really care how you get there. If the target is about 50 hp, you could have a big, burly giant (huge size for d12s, CON 16 for +3 per die) and only need 5 or 6 hit dice; or you could have a feeble monkey-like creature (small size for d6x, CON 8 for -1 per die) and need 20 HD. Since proficiency is based on CR rather than HD, the game doesn't care. (Shades of 4e monster design, basing hp on level!)

If that is true, then what is the point of monster Hit Dice? It becomes a vestigial rule that doesn't serve any function in 5th edition. Might as well make hit points based on level and cut out HD for monsters altogether.

 

[Bumamgar]

Because many DMs don't use a static number of hp for each monster, but instead roll the hp individually using the HD. That way you end up with sine goblins that are tougher than others but still have most goblins around the average hp

 

[surfarcher]

@surfarcher

I've been following your blog recently, and really appreciate your fine toothed comb analysis trying to understand how monsters are built in 5e.

One thing that perplexes me is Hit Dice. Specifically, how many Hit Dice a monster gets and the relationship between Hit Dice and CR. Any inkling how this works yet?

For example, take a CR 1 monster. According to your chart, it should have 9d4 (22.5) hit point if it is Tiny, 7d6 (24.5) if Small, 5d8 (36) if Medium, 3d10 (16.5) if Large, 3d12 (19.5) if Huge, and theoretically 2d20 (21) if Gargantuan. Which seems to completely undermine the idea that bigger things have more hit points.

Clearly there is not a perfect correlation between Hit Dice and CR, given the discpancy between old and young dragons (little HD difference but big CR difference) and "glass cannon" monsters with really potent abilities having fewer HD to compensate. There are dials one can turn, for example, one for HD and one for Special Abilities. Both effect CR.

Using Traits as a dial for CR can be fraught with danger as many traits are very difficult to enumerate in terms of HP or Damage.

5e pretty obviously has template-oriented monster of the system so we can expect to see templates coming out at some stage, probably in the near future (I'm tipping before October). The instructions for these will say they are great to add to monsters where it makes sense to you, will probably come with a warning about applying too many templates. So Traits can be pretty subtle (e.g., Water Breathing)... Or quite powerful (e.g.'s, Regeneration, Sneak Attack).

What I'm trying to figure out is...

(a) What is the Hit Dice baseline for each CR? I think this is one number for each CR, irrespective of a creature's size. For example, 4 HD might be the CR 1 baseline, with a medium creature getting 4d8, a large creature 4d10, etc. I choose "4" as my example because it is the average party size in 5e (the standard range is 3-5 characters), and a CR 1 creature is supposed to be a moderate challenge for an average size level 1 party.

As @the Jester and @Bumamgar clarified it's all about target HP, when you are building towards a CR. You can also build these critters without looking at a table and then go back at the end and work out what CR they are... But you'll probably have to tweak some aspects of your monster to bring it close to reasonable CR boundaries.

(b) What "standards of exchange" between Hit Dice and Special Abilities (or other factors) can be deduced from the existing monsters? For example, if I have a CR 1 monster and I want to make it have less hit points and more Special Abilities while keeping its CR the same, what is a 2 HD (for example) drop worth roughly? An area attack ability? Blindsight? A defensive trait? A Pack Attack trait? A higher AC?

My Traits post is proabbly going to help you. The thing is, most Traits don't have combat impact... But a few very notable ones do, but they are calculated into damage/hitpoints.

With other Traits you'll have to work out how many HP or Damage you think it's worth on a case-by-case basis, if you want to take that approach.

Anyhow, I'm looking for answers as I read thru the monsters with an eye toward making connections, not in anywhere as scientific a method, but rather on what I believe is the more fuzzy "art" of monster design.

Good man! Monster building in 5e seems to be more about art by default. That has a lot of pitfalls, but kay sera sera!

 

[Quickleaf]

Good man! Monster building in 5e seems to be more about art by default. That has a lot of pitfalls, but kay sera sera!

Thanks for the feedback!

Really, there has always been significant art to designing monsters. Clearl it was there in AD&D, was present in 3e despite the structured approach attempted (citation: how many folks complained about 3e CR as an inaccurate measure), and was present in 4e if you tried to do anything beyond a basic monster built by numbers. The crux of it is that you need a strong math foundation for monster basics to establish a baseline around which to build a monster... I'd much rather argue over the CR value of a special ability I want to add rather than argue over the fundamental monster math... But ultimately the interesting stuff that makes monsters unique comes down to the art.

I guess I have been looking for some sort of guidelines like "subtract 1 HD to add Perception skill and Darkvision" or "subtract 3 HD to give an area attack." What I'm realizining is that monster HD are rather superfluous.

It seems to me the only purpose for Hit Dice (since they're not clearly tied to CR) is to determine the multiplier for Constitution provided Hit Points. Seems like a weak reason to keep them as a rule for monsters...unless they're planning on building design elements that interface with HD in the future.

 

[surfarcher]

And as far as I can see they aren't...

The big problem I see with the way 5e is doing things is it's actually too loose, it's too much about "the art" and "the rule of sense". And, as always, that results in some critters within the same CR that are very swingy.

The Vampire Spawn is a weak CR5 with 82hp and 21 damage. The Shambling Mound is a strong CR5 with 136hp and 26 damage. The Hill Giant isn't quite as tough a guy as the Shambling Mound, but it's still a very respectable 105hp and 36 damage.

Regeneration obviously accounts for some of the Vampire Spawn's hitpoints, but it's still fairly weak for a CR5 in both hp and damage.

Big differences and their other Traits don't really account for it, but they have the same CR

This means you can build fights according to the CR budget that should be tough, but end up being so much harder than a casual bystander might think. Especially using synergistic monsters.

 

[pemerton]

Regeneration obviously accounts for some of the Vampire Spawn's hitpoints, but it's still fairly weak for a CR5 in both hp and damage.

It also gains hp from biting. So assuming it survives a round or two (big assumption? my 5e-fu is not very strong) it has more like 104 hp (+10 regen, +13 from biting).

That puts its hp closer to the Hill Giant. (Especially when the giant has AC 13 rather than 15 for the vampire and mound, and the vampire has noticeably better DEX and WIS saves than either the giant or the mound.)

As far as damage is concerned, the designers seem to think that losing damage from a bit permanently (until a long rest) is a big deal.

 

[Ainamacar]

Thanks for the feedback!

What I'm realizining is that monster HD are rather superfluous.

It seems to me the only purpose for Hit Dice (since they're not clearly tied to CR) is to determine the multiplier for Constitution provided Hit Points. Seems like a weak reason to keep them as a rule for monsters...unless they're planning on building design elements that interface with HD in the future.

I think it's fair to call hit dice the glue that binds hit points and Constitution. That's useful because those two elements serve pretty different purposes in D&D. Hit points are extremely abstract but have a direct impact on how creatures endure combat, and so are an excellent target when designing creatures. Constitution is often understood to be more grounded in the fiction (e.g. as the in-world representation of "tough as an elephant" vs. "tough as a dog") and has impact on a bunch of other toughness-related quantities that shouldn't necessarily be tightly coupled to hit points.

Pragmatically, then, suppose one is designing a creature and has both a sense of how tough it should be in the abstract game-driven sense (hp) and how tough it should be in a more fiction-driven sense (Constitution). Hit dice adds a degree of freedom which allows one to hit both targets in the same mechanical framework. And, of course, one could design from other starting points. For example, one might approach monster design more "naturalistically", where the abstract toughness (hp and ultimately CR) is the output of monster design rather than an input. In that case there might be a set of first principles based on Con and hit dice, and then hp are derived as a matter of course.

Additionally, some people philosophically prefer creatures and characters to be built from the same mechanical components since it sweeps some of the arbitrariness of design under the rug. (And I think hit dice stay sufficiently out-of-the-way that people who don't find that notion compelling won't find it too much a nuisance.) Also keep in mind that hit dice already have defined mechanical effects for PCs. Giving monsters that same quantity lets groups handle, for example, out-of-combat monster healing in the same as PCs if desired. Even further afield are groups that like to experiment with monsters as PCs, something that would be difficult if hit dice were defined only for the latter. And as you note, it also means other systems can be built on top of it at a later date.

Finally, hit dice define a way to let hit points vary among otherwise identical monsters. That variety can be both aesthetically and functionally useful, in particular when it diminishes metagaming. Rolling those kinds of quantities isn't for everyone, and I'm glad monsters list mean hit points, but it's a nice boon with almost no cost for those who don't do it.

So, overall, I think this iteration of hit dice looks fairly decent. It appears to work with multiple philosophies of monster design, supports some playstyles that might otherwise be difficult, and avoids the ultimately unresolvable difficulties 3.x had in half-heartedly trying to make HD equal CR.

 

[surfarcher]

It also gains hp from biting. So assuming it survives a round or two (big assumption? my 5e-fu is not very strong) it has more like 104 hp (+10 regen, +13 from biting).

That puts its hp closer to the Hill Giant. (Especially when the giant has AC 13 rather than 15 for the vampire and mound, and the vampire has noticeably better DEX and WIS saves than either the giant or the mound.)

As far as damage is concerned, the designers seem to think that losing damage from a bit permanently (until a long rest) is a big deal.

It's damage is already very low and it has to give up damage on a Claw attack to grab so that it can Bite. That's really not optimal. The best case I can see for it's damage is that it has a willing victim so it can Claw and Bite with it's Multiattack. That barely gives it raw damage of 21. Very low.

...snip...
So, overall, I think this iteration of hit dice looks fairly decent. It appears to work with multiple philosophies of monster design, supports some playstyles that might otherwise be difficult, and avoids the ultimately unresolvable difficulties 3.x had in half-heartedly trying to make HD equal CR.

Oh I think it's ok. That's not where I see problems with this edition's monsters...