D&D 5e Monsters: Part 9: Construction: Attack Bonus
Surf has a short but thorough look at Attack Bonus...
Part 9: Attack Bonus
We are almost finished with our build-oriented approach, however we do need to sit back and consider how Attack Bonus progresses and look at how that applies to our Example Monster before we move on to the final part - assessing the actual CR we have achieved.
Attack Bonus
When constructing monsters with a build-oriented approach we assign Ability Scores well before determining dependent attributes, such as attack actions. And when evaluating a monster we often start by checking out its ability scores and how they align to the values we previously determined for that CR. Assuming we chose appropriate values at those points we shouldn't need to be too concerned about the "to hit" progression, right? Well yes, inside a build-oriented approach that's correct. But with a result-oriented methodology that's not the case, we certainly want to know those numbers for that approach. Additionally we need to know what these parameters should be for CR assessment, as it's a factor there.
Monster Attack Bonus Scatter
Monster Attack Bonus Average
As part of my data entry I record the regular Attack Bonus of each creature, as it aligns with the standard method of generation we looked at in the last article. As one would expect this makes it rather simple to graph and analyze.
Plotting all the data in a scatter graph, with a linear trendline, the progression is quite easy to observe. The data points cluster relatively closely to the trendline for most CRs, although there are a few exceptions. In fact the average Standard Deviation for each CR is 1.2 and the average Var is 1.8. This tells us that we can be very comfortable with a +/-2 variability on the to-hit bonus we determine. And of course we can also adjust outside the +/-2 bounds if we make compensating adjustments elsewhere, but we need to be careful and it's probably best to have some experience building D&D 5e monsters before attempting it.
This narrow band progression is due to two main factors. Firstly, the attack bonus is almost always derived from an ability modifier that is very close to the standard maximums we looked at earlier in this series. Secondly, monsters almost always have the appropriate proficiency bonus for their CR applied to their attack bonus.
This leads us to expect a summarized version of this graph to be very close to the actual progression and that's exactly what we see. That said the relatively low volume of high-CR monsters in our sample does cause some variability at the end of the graph.
CR
Attack Bonus✝
0
+3
⅛
+4
¼
+4
½
+4
1
+4
2
+5
3
+5
4
+6
5
+6
6
+7
7
+7
8
+8
9
+8
10
+9
✝ Varies by +/-2
There are already posts on various forums suggesting simplified linear progressions for values like this. I've yet to see one that is a close match to what we've observed here though. All those I have seen produce results too low or high at one end of the scale or another. So what is a good match?
To me a good match needs to be about +4 at CR1, run through +13 at CR17 and not quite hit +20 at CR30. We know the CR30 cap is +19, being +10 for max ability score of 30 (Player's basic rules version 0.2, page 7) and +9 for CR30 proficiency (DM's basic rules version 0.1, page 4). But it also needs to account for values below CR1. And while the average +2.2 at CR0 might be tricky to hit with a linear progression it certainly shouldn't be too far off the +3.7 at CR¼. Of course rounding will hide most of the details below CR1, but we should be close anyway as this lends confidence to our result.
Kudos here to +Ford Davis for reminding me of the CR30 cap.
A small amount of time in Excel gives us a linear formula which meets most of the criteria above...
Attack=0.53 × Target_CR + 3.49
As anticipated this progression doesn't quite produce a +2.2 value at CR0, giving a +3.49 which rounds to +3.0 instead, but it is a very close match for the remainder of our criteria. As previously discussed values for attributes below CR1 do tend to skew a bit because of the low granularity and this slight skew in accuracy isn't too big a deal as CR0 monsters pose almost no threat to PCs, even at level one. Note that a process-oriented build is normally going to result in a +2 if it uses ability scores close to those we previously discussed and our +/-2 margin does allow for the difference, while Bounded Accuracy further reduces possible issues to almost zero.
Personally I have no problems using this progression as-is rather than trying to compensate with hand editing. Naturally readers are welcome to tweak it to +2 for their own use.
Prediction: The majority of CR30 monsters will have a normal attack bonus in the range of +18 to +19.
Example: Human Pyromancer
We don't really have anything to add to our example monster in this instalment.
Human Pyromancer
Medium humanoid (human), any alignment
Armor Class 12
Hit Points 77 (14d8+14)
Speed 30ft
STR 9 (-1)
DEX 14 (+2)
CON 12 (+1)
INT 19 (+4)
WIS 12 (+1)
CHA 12 (+1)
Saving Throws Dex +5, Int +7
Skills Arcana +7, Perception +4
Damage Resistances Fire
Languages Common, Ignan
Challenge 5 (1,700 XP)
Spellcasting. The pyromancer is a 5th-level spellcaster. Its
spellcasting ability is Intelligence (spell save DC15, +7 to hit
with spell attacks). The pyromancer has the following wizard
spells prepared.
Actions Dagger.Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 4 (1d4 + 2) piercing damage.
Reactions Flame Shroud (Recharge 5-6). When a ranged attack would hit
the pyromancer, or it is targeted by a spell that has a range
other than touch, the air around it bursts into shimmering,
shifting flame for a few seconds. Until the start of the
pyromancer's next turn ranged attacks against it, including the
triggering attack, are made with Disadvantage and it has
Advantage on saving throws against spells with a range other
than touch. During this time it takes no damage from magic
missile.
All that we can really do here is consider the pyromancer's attack bonus.
The SpellcastingTrait includes a spell "to hit" value of +7. This is a one higher than the +6 we believe is standard for CR5, but well within the +/-2 standard variation we declared earlier. So this is a good fit.
Our Dagger action is really only present for opportunity actions and that means it's +5 "to hit" being one low of appropriate for its CR should be just fine too.
So overall I think the pyromancer sits well, from an attack bonus perspective.
Next time we'll have a look at how we can evaluate a monster's Actual CR once we think we have finished working on it.
Surf continues on into the final parts of the monster stat block...
Part 8: Construction: Actions
Some of these articles seem to take on a life of their own and grow longer in the writing. I originally intended to include the Attack Bonus analysis in this instalment, however I've decided to post this part on its own and continue working on Attack Bonus as its own separate article.
Monsters are subject to the same action economy as player characters, although some monsters are able to extend this action economy in ways that PCs cannot - most notably Legendary Creatures. Just like PCs each monster can move and take one Action on its turn. And just like PCs monsters also have a Reaction and a Bonus Action that they may use, if they have a way of doing so.
Formally expressed actions use certain common elements to standardize documentation, though some actions may omit almost all of these components. The components themselves are pretty straightforward and tend to focus primarily on supporting attacks. These elements include the following...
Name: All formally presented actions start with a short descriptive name for that action, frequently this is a single word. For example "Bite".
Usage: Some actions are of limited usage and this is normally noted in braces immediately after the attack name. For example "Recharge 5-6".
Attack Type: Most attack actions employ a standardized short form to indicate the general attack range (for example melee or ranged) and type (for example weapon or spell), along with the keyword "attack". Common examples include "Melee Weapon Attack", "Ranged Weapon Attack" and "Ranged Spell Attack".
Special attacks instead typically describe very briefly the attack type, range and shape. For example "The dragon exhales fire in a 60-foot cone".
Attack/Defense enumeration: Attack actions normally specify either a "to hit" bonus or details of a saving throw that the target must make. For example "+14 to hit" or "DC21 Dexterity save".
Target/Range information: Attack actions normally describe targeting information. For standardized short-form attacks this will be a range type (reach or range), a range outline in feet (including long range if applicable) and the number of targets. Examples include "reach 5', one target" and "range 120/360 ft., one target".
Special attacks normally dovetail their action description into their target specification descriptively. For example "each creature in area" or "each creature that can see the..."
Hit/Miss section: These sections of attack actions describe what happens when the attack hits or, in some cases, when it misses. This section describes damage amounts, damage types, conditions and ongoing damage/conditions. It may also include nested attack sections, which are effectively additional attacks.
Move
Move actions are not formally expressed actions in D&D 5e and are almost expressly not to be used for purposes other than movement. Indeed a number of monster actions which could be considered movement are implemented using Actions and Bonus Actions, such as the Etherealness action of the Ghost.
In D&D 5e the use of move actions is normally described in the Speed section near the very top of the monster stat block.
Action
Combat-viable monsters almost universally have at least one Action and the majority of Actions are some form of attack, either as a direct attack or indirectly by enabling attacks, Multiattack being the most common of these.
Actions appear to fall in five specific categories and these always seem to occur in the following order with in the Actions section, when present...
Multiattack
Regular attacks
Special attacks/Non-attack actions
Limited use attacks
1. Multiattack
Multiattack. The dragon can use its Frightful Presence. It then
makes three attacks: one with its bite and two with its claws.
Multiattack actions simply specify the name "Multiattack" and the other Actions which may be used when the creature's Multiattack action is used, including the number of times each may be used (if more than once).
The Multiattack action is one of the most common actions in D&D 5e and the mechanism by which many of this edition's monsters achieve the bulk of their Damage. The action's simple elegance makes it easy to tune in to the desired target damage range at design time and at game time allows the DM a good deal of flexibility dishing out damage with as much or as little focus as desired. We already see in the PC classes that increasing the number of attacks over levels is a common scaling method in D&D 5e and that may be one of the reasons Multiattack is so common in its monsters, but I believe it is also present specifically because of the control it yields to DMs and to monster designers.
The Multiattack action can be as simple as two uses of a single regular melee attack or as complex as five, or possibly more, different Actions.
2. Regular Attacks
Tail.Melee Weapon Attack: +7 to hit, reach 10 ft., one target.
Hit: 18 (4d6 + 4) bludgeoning damage. If the target is a
creature, it must succeed on a DC 14 Strength saving throw or
be knocked prone.
Regular attacks are slim-line in design and implementation, generally steering clear of unnecessary complexity. These actions include a standardized short-form Attack Type, typically an Attack Enumeration of the "to hit" variety and short-form Target/Range Information. They generally also include a relatively simple Hit section, occasionally with a Miss section, and may include nested damage.
Almost all combat-viable creatures have at least one regular attack and many of the lowest CR creatures have nothing but regular attacks. In some cases regular attack actions are fallbacks used for things like opportunity attacks or as building blocks for Multiattack actions.
3. Special Attacks/Non-Attack Actions
Rotting Gaze. The nothic targets one creature it can see within
30 feet of it. The target must succeed on a DC 12 Constitution
saving throw against this magic or take 10 (3d6) necrotic
damage.
Special attacks and non-attack actions generally eschew the use of short-form annotation. By definition the more free-form Attack Type description is used and in most cases the free-form Attack/Defense enumeration and Target/Range information are also observed. Both the Hit section and Miss section may be present, but they may also be omitted in favor of a more free-form description, particularly in the case of non-attack actions.
Special attacks may account for a significant portion of a monster's alpha damage (aka "burst damage" or "spike damage"), especially where special attacks are conditional. However, in most cases alpha damage is the domain of limited use attacks or of the SpellcasterTrait.
4. Limited Use Attacks
Cold Breath (Recharge 5-6). The wolf exhales a blast of
freezing wind in a 15-foot cone. Each creature in that area
must make a DC 12 Dexterity saving throw, taking 18 (4d8)
cold damage on a failed save, or half as much damage on a
successful one.
Limited use attacks are those that specify a Usage restricting how frequently they may be used. Attacks of this type generally inflict damage well above that which the creature would otherwise cause and its normal damage is normally comparatively lower to compensate. In other respects the limited use attack typically resembles either regular attacks or special attacks.
The limited use attack is one of two vectors in D&D 5e for implementing alpha damage (aka "burst damage" or "spike damage"), the other normal vector being the Spellcasting trait.
Action Analysis
Now that we have examined the different types of Actions we need to consider the number of actions that are appropriate for a creature of our target CR. Is it just random (and by inference static with an acceptable margin of variance)? Or is there some kind of progression?
Common sense and instinct suggest that higher level monsters are more complex and thus more likely to have more Actions, but let's check the facts analytically.
Monster Number of Actions Scatter
Monster Number of Actions Average
Once we have recorded the number of Actions each monster has it's a relatively simple matter to create a scatter graph showing number of Actions by CR. Placing a trendline on this gives us an initial indication of whether there might be some kind of progression.
The graph suggests that there probably is a progression, although it is kind of difficult to tell exactly what. And the relative sparseness of our higher-level samples means the high CR end will be quite prone to skew. Still the shape of the samples tells us that a variation of +/-2 seems quite normal. In fact the Standard Deviation for this across all CRs is 0.89 and the average variability is 1.14. So we can be quite happy with +/-2 as our regular variation, understanding that there is scope to vary outside this if we feel that it's appropriate in a particular case.
Averaging the data out by CR and then producing a comparable graph reveals a likely progression. For the most part the data is quite well aligned and the progression itself is quite shallow. D&D 5e's preference for simple elegance shows itself here - even the more complicated monsters in the new edition tend to be relatively simple to understand and run. I find this a refreshing difference to its immediately preceding editions.
CR
Num Actions✝
0
1
⅛
1
¼
2
½
2
1
2
2
2
3
2
4
2
5
2
6
2
7
3
8
3
9
3
10
3
✝ Varies by +/-2
The summary graph tells us pretty clearly that a progression from 2 at CR1 to 7 at CR30 is probably appropriate and that we'd want to drop down to about 1 action somewhere around CR¼. How sure of this can we be? What margin is there for error? And how much does it matter if we are wrong?
Well we already mentioned the low Standard Deviation and Variability, which give us some surety. But as I said we are quite light on higher CR samples and this could skew that end of the trendline. Fortunately with such a short range of difference this is somewhat like Bounded Accuracy, we don't necessarily have to be exactly right - our margin for error isn't that big. Additionally these are only guidelines of what's generally appropriate at a nominated CR and we are designating a significant variation as standard so the impact of being out by a couple of Actions isn't big.
It only takes a couple of minutes to determine a linear progression that matches this pattern...
Actions=0.17 × CR + 1.46
As a matter of practical advice I'd encourage monster designers to follow D&D 5e's principle of elegant simplicity wherever possible with Actions. Look to expressing your monster concept clearly with a small number of concise Actions where possible.
Prediction: I think most of what we have covered so far is self-evident. The only predication I can make is about the accuracy of the progression we have detailed above. I believe we'll find it's not too far off.
Reaction
Just like PCs monsters have a Reaction they may use each turn and they can "spend" it in any of the standard ways - by readying an action, making an opportunity attack, dismounting as their mount falls or by using a spell with a casting time of "reaction". Some monsters can also use their Reaction in special ways, just as many PCs can, and if present this will be described in the monster's Reactions section.
Parry. The knight adds 2 to its AC against one melee attack
that would hit it. To do so, the knight must see the attacker
and be wielding a melee weapon.
The layout for a Reaction is normally its Name, an explanation of its trigger conditions and the details of the Reaction's results. While this might include any of the elements described in the Action Overview most Reactions tend to be fairly freeform, with a layout similar to the Special Attacks/Non-Attack Actions discussed above.
Monster Reaction Scatter
Monster Reaction Average
While most PCs manage to pick up a reaction by level 5 we find that Reactions are far less common amongst D&D 5e's monsters.
If we note the number of reaction entries each creature has and then plot the results on a scatter graph it's immediately obvious that very few monsters have a special Reaction. In fact of our 225 sample monsters only 7 have a Reaction (that's 3.1%) and none of these has more than one.
By averaging this data out and graphing it again we get visual confirmation of just how unusual it is for D&D 5e monsters to use special Reactions. Besides one tiny "blip" we can see that the overall average for any given level is close to zero, as it is across all levels.
This means that the use of special Reactions isn't something that monsters in this edition rely upon. We can probably simply consider it a flourish and as such a way of adding a certain "flavor" to the odd monster.
Based on the principle of elegant simplicity I believe we should not normally give our monsters special Reactions. Instead we should save these for when there is a compelling reason - perhaps we want a creature to "feel" like a Fighter or a Rogue and give it a Reaction similar to one that class has. Or perhaps our mental picture of the monster compels us to give it a special Reaction
Prediction: Special Reactions will remain quite rare as we see more monsters released by Wizards of the Coast.
Bonus Action
As monsters may take a reaction each turn they may also take a Bonus Action, if they have a way of doing so.
Rampage. When the hyena reduces a creature to 0 hit points
with a melee attack on its turn, the hyena can take a bonus
action to move up to half its speed and make a bite attack.
A monster's Bonus Action use is not detailed in a separate dedicated section, instead it is incorporated within other sections already discussed, typically the Traits section. A monster's Bonus Action may sometimes also be spent as a conditional extension of an Action.
While some Bonus Actions do enable additional attacks or Damage (which must be factored into the creature's average damage) some do not, instead they enable additional movement or other activity.
Monster Bonus Action Scatter
Monster Bonus Action Average
This brings us to consideration of Bonus Action progression and occurrence. Once again we tally up the number of Bonus Actions that each monster has and see what the data tells us. The first thing we see is that 24 of our 225 sample creatures (that's about 10.7%) have at least one Bonus Actions. And all but one of these have only a single Bonus Action.
The scatter graph of all samples makes this quite clear and we can see the CR2 Will-O'-Wisp clearly standing out above the rest. This tells us that most of the time our monsters won't need a Bonus Action, but if we choose to use one it should probably just be a single one. This is nicely in keeping with the principal of elegant simplicity.
The summary graph clearly reflects the approximate 10% occurrence of Bonus Actions and also reveals the low numbers of our high-CR samples, which results in some variability from about CR10 onwards.
Essentially monster mechanics which utilize Bonus Actions add complexity to monsters. If we consider the principals of elegant simplicity and easy operation together with the frequency of Bonus Actions it suggests we should think a little before using Bonus Actions on our monsters. If our monster feels a bit on the plain side and too simple maybe it's appropriate to spice it up a bit with a Bonus Action. If we want to give our monster the feel of a PC class maybe we could factor a Bonus Action into its composition.
Bonus Actions don't add the complexity of Reactions so with these I believe it's more a matter of using our judgment.
Prediction: Once the Monster Manual analysis is complete I believe we will see that the distribution of Bonus Actions stays at around 10% across all CRs, that said it is possible that it will increase somewhat at higher CRs.
Building Attack Actions
Building attack actions can be fairly freeform however there are some underlying construction guidelines we should observe, especially in the case of most regular attack actions.
Many monster designers feel more comfortable building monster attacks based on PC attacks and this works particularly well with weapon attacks. One selects a weapon, applies the appropriate modifier (Strength modifier for most melee weapons or Dexterity modifier for finesse and many ranged weapons) for to-hit and damage, then adds proficiency to the to-hit value. Monster size does appear to play a role here and that role seems to focus on damage dice.
Size
Modification
Tiny
Light weapons only
Small
Heavy weapons excluded
Medium
N/A
Large
2x weapon dice
Huge
3x weapon dice
Gargantuan
4x weapon dice
Weapon attacks seem to be impacted by creature size. Creatures smaller than medium appear to have restrictions on the weapons they can use and creatures bigger than medium size gain multipliers to the number of weapon dice. These modifications are clearest when looking at creatures assigned attack actions corresponding to weapons in the players guide. But this can also be extrapolated from other attack actions.
I have included a table with my understanding of these modifications. Please do note that this table is based on my observations and reflections.
While these observations correspond with those made by other members of the D&D 5e analysis community (kudos to Coronoides from the RPG.net forums and to others) they may not be a perfect match to what Wizards of the Coast is using. But it should be useful until we receive official guidelines from WotC.
Many creatures have attack actions similar to spells and many monster designers find it easiest to build these using PC spells as a base. The most important thing here is to ensure that the Spell Save DC or Spell Attack Modifier are appropriately calculated, using the appropriate ability modifier as the spellcasting modifier, as we discussed in the Spellcasting section of Part 6.
As monster designers gain more confidence building monsters in D&D 5e it's likely they'll tend to move away from reproducing PC attacks, except where appropriate, and instead move towards a more "pure form" of building monster attack actions. To those embarking down this path I would share the following notes and general pieces of advice...
Decide on the base ability and work out its modifier. For direct physical attacks it should be Dexterity or Strength. For magic, mental and other similar attacks it should be Charisma, Intelligence or Wisdom. Usually it's the highest ability in that group, unless there's a compelling reason otherwise.
Assume the monster has proficiency with their attacks, unless it suits design for them not to have proficiency.
Damage always seems to have a base damage which is then built upon, which should be in the form
NdN + Base_Ability_Modifier. For example 2d8+4
There is no mixed damage in D&D 5e, different types of damage in the same attack are concatenated. The base damage comes first with other damage appended to it. For example we would not have "3d8+2 fire and force damage"; instead we might have "1d8+2 fire damage plus 2d8 force damage".
It's legitimate to nest additional damage within base damage, typically using a save. For example "1d8+2 bludgeoning damage, the target must make a DC12 wisdom save or take an additional 2d8 psychic damage".
Example: Human Pyromancer
Applying this article's content to our example monster will produce a result that is essentially complete.
Human Pyromancer
Medium humanoid (human), any alignment
Armor Class 12
Hit Points 77 (14d8+14)
Speed 30ft
STR 9 (-1)
DEX 14 (+2)
CON 12 (+1)
INT 19 (+4)
WIS 12 (+1)
CHA 12 (+1)
Saving Throws Dex +5, Int +7
Skills Arcana +7, Perception +4
Damage Resistances Fire
Languages Common, Ignan
Challenge 5 (1,700 XP)
Spellcasting. The pyromancer is a 5th-level spellcaster. Its
spellcasting ability is Intelligence (spell save DC15, +7 to hit
with spell attacks). The pyromancer has the following wizard
spells prepared.
Actions Dagger.Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 4 (1d4 + 2) piercing damage.
Reactions Flame Shroud (Recharge 5-6). When a ranged attack would hit
the pyromancer, or it is targeted by a spell that has a range
other than touch, the air around it bursts into shimmering,
shifting flame for a few seconds. Until the start of the
pyromancer's next turn ranged attacks against it, including the
triggering attack, are made with Disadvantage and it has
Advantage on saving throws against spells with a range other
than touch. During this time it takes no damage from magic
missile.
Because we made a conscious choice to rely heavily on the Spellcasting trait for most of the pyromancer's damage we don't have a great deal to do in the Actions section. All we really need to do is to give it a melee attack action that it can use for opportunity attacks. To this end let's give it a Dagger attack.
A CR5 creature's Proficiency bonus is +3 and the dagger is a finesse weapon, so we'll use the dexterity modifier of +2 for this. There's no compelling reason to beef this up so we will just go with +5 to hit and 1d4+2 damage.
Now several times during these articles I have indicated that we would give our pyromancer some kind of "trick" against ranged spells and attacks. Something to help it get through that first round, until some of the PCs close on it. What I've had in mind is something like the Shield spell, however I see several issues with simply assigning the pyromancer Shield. First up our monster would be able to use this three times, not simply once. Secondly Shield works against weapon attacks, but doesn't provide any benefit against ranged spells. Finally Shield isn't fire-themed.
Because of the first two issues simply reskinning Shield isn't going to meet our needs. So we'll take what we can as inspiration from Shield, modify other parts and fill the gaps ourselves.
Shield is a reaction with a force flavor that gives a +5 defensive bonus until the start of the caster's next turn and nullifies magic missile. The +5 isn't much help against spells, but a +5 is about the same as advantage/disadvantage compared with a plain roll. So we can use advantage/disadvantage in its place and word a reaction that functions against ranged attacks, with a fire flavor.
If we imagine that the pyromancer is momentarily shrouded in shimmering fire that makes it difficult to target we can envision how this can all come together.
Finally we want to restrict use of this reaction somewhat so that it isn't used every round. We could make it a daily power, but I decided that it would be most interesting if there was a small chance the pyromancer could use it more than once per encounter, so I made it a recharge reaction.
Next time we'll look at how the pyromancer matches up to the to-hit curve and then we'll move on to assessing its actual CR.
Part 8: Construction: Actions
Master Index
