D&D 5E Offensive CR: determining damage output for a spellcaster

[pukunui]

Hi all,

I decided it was about time I had a go at using the monster building guidelines in the DMG to check the CRs I eyeballed for a number of monsters and NPCs in my campaign. I've run into a bit of a stumbling block with the first one, who I've based on the CR 6 NPC mage in the back of the MM.

How do I determine a spellcaster's damage output per round? Is it based on physical damage (eg. the NPC mage is equipped with a dagger), cantrip damage (eg. fire bolt or whatever), and/or levelled spell damage (eg. fireball)?

On page 279, it addresses the spellcasting trait, but in a very unhelpful way. It just says that the effect it has on CR depends on the types of spells, but then says to refer to the MM for more info, but the MM essentially just refers you back to the DMG. Blargh.

Anyone got any ideas?

Thanks,
Jonathan

 

[MonsterEnvy]

When a creature has a damage output that can very you give it 3 rounds of what it can do the best. AoE effects are assumed to hit two creatures and for casters you use their save DC in place of their to hit bonus.

Pretty much use the average damage of the most powerful stuff it can do in 3 rounds. Divide the damage by 3 to get it's DPR. Then alter it's Offensive CR based on it's DC like you would with a To hit bonus.

 

[pukunui]

OK, so if we use the CR 6 mage as an example, that's probably one cone of cold and two upscaled fireballs (at 4th level). Those are all AoE spells, so I assume they hit two creatures each. Do I count the damage for them separately? As in, take the average damage of each spell, multiply by 2, then divide by 3? If so, that gives me a total of 66. That would put the MM mage's offensive CR at 9 (while its defensive CR is only 1/2, as far as I can tell), which gives it a final CR of 4.75, which is a bit on the low side but not by much.

Now, unfortunately for my NPC, he is an enchanter with very few spells that actually deal any damage, so his CR is going to be substantially lower than the generic mage, I think. I'll post his specifics after dinner.

EDIT: OK, here is:

AC 12 (15 w/ mage armor; +5 from shield)
HP 40 (9d8)

STR 9 DEX 14 CON 11 INT 17 WIS 12 CHA 14

Instinctive Charm

Spellcasting (8th level; DC 14; +6 to hit)

Cantrips: fire bolt, message, prestidigitation, shocking grasp
1st Level (4 slots): charm person, mage armor, shield
2nd Level (3 slots): blur, misty step, suggestion
3rd Level (3 slots): counterspell, fly, hypnotic pattern
4th Level (2 slots): confusion, greater invisibility

He also has a magic staff that lets him cast the light cantrip, plus color spray 2/day and dimension door 1/day.

His cantrips are his main source of damage output, although spells like confusion and his Instinctive Charm ability can potentially lead to indirect damage. Still, his offensive capabilities are pretty low.

Should I be factoring spells like blur, shield and counterspell into his defensive CR (via effective hit points)? What about spells like charm person, suggestion and hypnotic pattern - they're not damage dealers, and they don't add to his defense directly, but they can potentially prevent damage by stopping enemies from attacking.

What would you say this guy's CR is?


EDIT 2: I wonder if maybe I should give this guy some bracers of defense and boost his Con to 12 to give him some more hit points, thereby hopefully increasing his defensive CR and thus hopefully his overall CR. I was hoping to keep it around CR 6 like the NPC mage I based him on, but that doesn't seem likely at this point unless I drastically revise his stats.

 

[Grazzt]

OK, so if we use the CR 6 mage as an example, that's probably one cone of cold and two upscaled fireballs (at 4th level). Those are all AoE spells, so I assume they hit two creatures each. Do I count the damage for them separately? As in, take the average damage of each spell, multiply by 2, then divide by 3? If so, that gives me a total of 66. That would put the MM mage's offensive CR at 9 (while its defensive CR is only 1/2, as far as I can tell), which gives it a final CR of 4.75, which is a bit on the low side but not by much.

Now, unfortunately for my NPC, he is an enchanter with very few spells that actually deal any damage, so his CR is going to be substantially lower than the generic mage, I think. I'll post his specifics after dinner.

EDIT: OK, here is:

AC 12 (15 w/ mage armor; +5 from shield)
HP 40 (9d8)

STR 9 DEX 13 CON 11 INT 17 WIS 12 CHA 14

Instinctive Charm

Spellcasting (8th level; DC 14; +6 to hit)

Cantrips: fire bolt, message, prestidigitation, shocking grasp
1st Level (4 slots): charm person, mage armor, shield
2nd Level (3 slots): blur, misty step, suggestion
3rd Level (3 slots): counterspell, fly, hypnotic pattern
4th Level (2 slots): confusion, greater invisibility

He also has a magic staff that lets him cast the light cantrip, plus color spray 2/day and dimension door 1/day.

His cantrips are his main source of damage output, although spells like confusion and his Instinctive Charm ability can potentially lead to indirect damage. Still, his offensive capabilities are pretty low.

Should I be factoring spells like blur, shield and counterspell into his defensive CR (via effective hit points)? What about spells like charm person, suggestion and hypnotic pattern - they're not damage dealers, and they don't add to his defense directly, but they can potentially prevent damage by stopping enemies from attacking.

What would you say this guy's CR is?


EDIT 2: I wonder if maybe I should give this guy some bracers of defense and boost his Con to 12 to give him some more hit points, thereby hopefully increasing his defensive CR and thus hopefully his overall CR. I was hoping to keep it around CR 6 like the NPC mage I based him on, but that doesn't seem likely at this point unless I drastically revise his stats.

Hit Points = CR 1/4
AC 15 bumps CR by 1 (because it's two higher than baseline AC 13 for CR 1/4)
He can fly and deal damage at range so his effective AC bumps by 2 again (page 279, DMG); bump CR by 1 again

Defensive CR = 1

His DPR is 11 (if you figure firebolt every round) so CR 1
His attack bonus if you figure CR 1 is +3 (Dex + prof bonus) so CR 1 still

CR = 1 for this guy more or less by the DMG. I'd probably bump it to CR 2 or 3 at least just because he can fly, he can cast confusion, greater invisibility, and charm person.

If you want to bump his CR, bump his offensive spells. The CR 6 mage can cast fireball and cone of cold. (See page 278 in the DMG for AOE and 3 round DPR; they use a dragon's breath weapon as an example, but same principle...multiple targets take damage)

 

[pukunui]

He can fly and deal damage at range so his effective AC bumps by 2 again (page 279, DMG); bump CR by 1 again

I missed that bit! Thanks. I should probably reread the entire section before trying to review anything.

If you want to bump his CR, bump his offensive spells. The CR 6 mage can cast fireball and cone of cold. (See page 278 in the DMG for AOE and 3 round DPR; they use a dragon's breath weapon as an example, but same principle...multiple targets take damage)

I want to make him more of a defensive guy, though. He's a smarmy, weasely sort of guy who, if attacked by the PCs, will attempt to draw them out into public so he can play the "Come and see the violence inherent in the system! Help! Help! I'm being repressed!" card.

 

[Tormyr]

OK, so if we use the CR 6 mage as an example, that's probably one cone of cold and two upscaled fireballs (at 4th level). Those are all AoE spells, so I assume they hit two creatures each. Do I count the damage for them separately? As in, take the average damage of each spell, multiply by 2, then divide by 3? If so, that gives me a total of 66. That would put the MM mage's offensive CR at 9 (while its defensive CR is only 1/2, as far as I can tell), which gives it a final CR of 4.75, which is a bit on the low side but not by much.

Now, unfortunately for my NPC, he is an enchanter with very few spells that actually deal any damage, so his CR is going to be substantially lower than the generic mage, I think. I'll post his specifics after dinner.

EDIT: OK, here is:

AC 12 (15 w/ mage armor; +5 from shield)
HP 40 (9d8)

STR 9 DEX 13 CON 11 INT 17 WIS 12 CHA 14

Instinctive Charm

Spellcasting (8th level; DC 14; +6 to hit)

Cantrips: fire bolt, message, prestidigitation, shocking grasp
1st Level (4 slots): charm person, mage armor, shield
2nd Level (3 slots): blur, misty step, suggestion
3rd Level (3 slots): counterspell, fly, hypnotic pattern
4th Level (2 slots): confusion, greater invisibility

He also has a magic staff that lets him cast the light cantrip, plus color spray 2/day and dimension door 1/day.

His cantrips are his main source of damage output, although spells like confusion and his Instinctive Charm ability can potentially lead to indirect damage. Still, his offensive capabilities are pretty low.

Should I be factoring spells like blur, shield and counterspell into his defensive CR (via effective hit points)? What about spells like charm person, suggestion and hypnotic pattern - they're not damage dealers, and they don't add to his defense directly, but they can potentially prevent damage by stopping enemies from attacking.

What would you say this guy's CR is?


EDIT 2: I wonder if maybe I should give this guy some bracers of defense and boost his Con to 12 to give him some more hit points, thereby hopefully increasing his defensive CR and thus hopefully his overall CR. I was hoping to keep it around CR 6 like the NPC mage I based him on, but that doesn't seem likely at this point unless I drastically revise his stats.

Page 249 of the DMG has a section on adjudicating areas of effect for theater of the mind. It seems like the DPR calculation of area of effect spells is half of what is in that table. So a fireball is a 20 foot radius. according to page 249, that would hit 4 creatures. But the DPR calculation required to get our CR 6 mage to be CR 6 instead of a lot more is only 36 (8d8) x 2 creatures = 72 (or assume everyone saves for half damage). The cone of cold is a 60 foot cone. According to page 249 that hits 6 creatures, but calculating out the CR 6 mage only allows for it hitting 3 creatures (or all 6 saved for half damage).

As for the NPC you posted, his CR calculation is:
Defensive: 1/4 by HP boosted 1 step because of mage armor and fly + ranged. So defensive CR is 1/2.
Offensive: 1 by DPR boosted 1 step because of attack bonus (which is based off of Int instead of Dex for this guy). Final offensive CR is 2.

Average CR is 1.25 which rounds to 1.

Have you taken a look at the monster CR calculator that I posted recently? http://www.enworld.org/forum/rpgdownloads.php?do=download&downloadid=1189

Blur cannot be used for CR calculation while using Fly + Ranged as both are concentration spells. Shield and Counterspell don't seem to be used in CR calculations. CR calculation seems to be based off of the most effecient damge dealt over 3 rounds. So Confusion would not be used for the calculation.

EDIT: I also noticed that a few of the calculations used on this NPC are a little off of "normal." AC for a Dex 13 creature is 11 and 14 with mage armor. Proficiency bonus for a monster up through CR 4 is +2. So the spell attack bonus is +5 and the save DC is 13.

What CR do you want this NPC to be? If you want him to be CR 2, rather than giving him Bracers of Defense, which can be grabbed by the players, bump his Dex to 16 for an AC of 16 with mage armor and give him 54 hp (12d8). This would make him a solid CR 2.

 

[pukunui]

OK. Thanks Tormyr. I'll check out your calculator.

 

[pukunui]

EDIT: I also noticed that a few of the calculations used on this NPC are a little off of "normal." AC for a Dex 13 creature is 11 and 14 with mage armor. Proficiency bonus for a monster up through CR 4 is +2. So the spell attack bonus is +5 and the save DC is 13.

Oops. It's meant to be 14.

What CR do you want this NPC to be? If you want him to be CR 2, rather than giving him Bracers of Defense, which can be grabbed by the players, bump his Dex to 16 for an AC of 16 with mage armor and give him 54 hp (12d8). This would make him a solid CR 2.

I was hoping to keep it at CR 6, but it looks like that's not really possible since I took away all the big damage spells. He's a major villain in the campaign, but he's not one that likes to fight. He prefers to weasel his way out of difficult situations.

Also, your calculator's not really working for me. Getting lots of "#NAME?" errors - for the ability modifiers, for final hit points if I change the creature's size or Con, and a number of other things.


EDIT: OK, how about this for my NPC mage?

AC 14 (17 w/ mage armor) ~ bracers of defense
HP 78 (12d8 + 24)

STR 9 DEX 14 CON 14 INT 17 WIS 12 CHA 14

Saves Int, Wis

Replace hypnotic pattern with lightning bolt. Assuming it hits 2 targets each round (half of what's on page 249), that's 56 damage, which is CR 8. However, his save DC is only 14, so his offensive CR drops to 7.

Meanwhile, with 78 hit points and an AC of 17 with mage armor, plus the ability to fly, he's got a defensive CR of 4.

11/2 = 5.5, rounded up to 6.


p.s. I'm OK with the PCs getting the bracers. The monk could use a higher AC.



EDIT 2: Next one is my revised Ice Witch (I'm running a beefed up Legacy of the Crystal Shard campaign). I'm aiming for CR 8, and I think I've got it sorted.

AC 15 (ice armor ~ a variant of mage armor)
HP 73 (9d8 + 9 plus 24 from her ice armor)

STR 9 DEX 14 CON 12 INT 12 WIS 17 CHA 12

Dmg Resistances fire
Dmg Immunities cold

Freezing Aura - Anyone within 5 ft must make a Con save or take 5 (1d10) cold dmg

Legendary Resistance [2/day]

Spellcasting (9th level; DC 14; +6)

Cantrips: [x], ray of frost, thaumaturgy
1st Level (4 slots): command, cure wounds, [x], fog cloud
2nd Level (3 slots): gust of wind, ice spear*, lesser restoration
3rd Level (3 slots): dispel magic, [x]
4th Level (3 slots): [x], [x]
5th Level (1 slot): cone of cold

FYI: [x] marks spells that are redacted due to my alpha playtest NDA. One of them deals 17 (5d6) dmg to all creatures within a 20 foot radius that fail a save. For the purposes of offensive CR, I'll be including two rounds of that spell plus one round of cone of cold (affecting 3 creatures - half the amount from pg 249 of the DMG).

Legendary Actions: Includes a variation of the solar's Searing Burst, which deals an average of 20 dmg. I'll be factoring that in to her damage output, along with the 5 dmg from her freezing aura and a spike growth-like lair action [it deals 5 dmg per 5 ft moved, but they'll be fighting her in a fairly small space, so I doubt it'll do much more than 5 dmg anyway].

Cone of cold: average of 36 dmg x 3 targets = 108 dmg. [X] 4th level spell: 17 dmg x 2 targets = 34 x 2 rounds = 68 / 3 = 58 + 30 dmg from legendary/lair actions and auras = 88 damage output per round. That puts her offensive CR at 14, but her save DC is only 14, so that drops it to 12.

Her two instances of Legendary resistance give her 40 extra effective hit points, bring her HP total to 113, which is CR 3, but her AC of 15 bumps that up to a defensive CR of 4. 12 + 4 = 16 / 2 = 8.

I didn't factor her damage resistance and immunity in as it seems like it's mainly the B/P/S resistance that affects defensive CR.

Did I miss anything there?


*Custom spell from the LotCS stats pdf

 

[Tormyr]

*Snip*

RE: Excel error.

Are you using an older version of Excel? ?NAME errors occur when Excel does not recognize part of a formula. The only interesting part of the formula in the ability modifiers section is the FLOOR.MATH() function. If you do a global search and replace on the file and replace FLOOR.MATH with FLOOR it may work.

RE: NPC that needs more teeth

You got there, but a few of the calculations are different than what you thought, so you might want to be aware of them in the future.
The average damage for lightning bolt is 28 (8d6) so it is doing 56 damage per round. However, there are two 4th level spell slots, and the CR guidelines use the most efficient damage dealing possible. So two rounds do 65 damage for an average of 62 damage. This puts offensive CR at 9 -1 for the low save DC for an offensive CR of 8.

You can go up to 84 (13d8 + 26) hit points. The Defensive CR would start at 1 and go up to 4. The average is CR 6.

RE: Hedrun

For resistances and immunities, even immunity to poison is enough to kick in the immunity multiplier. Cold and fire should probably count in the calculations for effective hp.

I only got an average of 83 DPR, but I may have missed something. Even then her DCR with the immunity is 7, and her OCR is still 11. Average CR would be 9. However, the CR is only 1 different from what you got, so I think you have a pretty good idea of how to calculate CR. Spellcasters are definitely the hardest to figure out.

The Abjurer's Armor and Ice Armor in Legacy of the Crystal Shard seem to be keyed to half of the NPCs hit points, but you can choose whatever number you want, and 24 is fine. For Hedrun's Ice Darts and Ice Spear, I used magic missile and melf's acid arrow with cold damage. You might also like to take a look at ice storm. With Hedrun's immunity to cold and difficult terrain, she could drop that in the room and walk through unimpeded and pick off PCs one at a time as they are lost in the storm.

 

[pukunui]

RE: Excel error.

Are you using an older version of Excel? ?NAME errors occur when Excel does not recognize part of a formula. The only interesting part of the formula in the ability modifiers section is the FLOOR.MATH() function. If you do a global search and replace on the file and replace FLOOR.MATH with FLOOR it may work.

Office 2007. I'll give your suggestion a try when I get a chance.

RE: NPC that needs more teeth

Since you're familiar with the adventure, this is Gant. The text says he hasn't progressed much beyond his apprenticeship, so I don't want to give him access to 5th level spells. I also want to make him more defensive than offensive.

You got there, but a few of the calculations are different than what you thought, so you might want to be aware of them in the future.
The average damage for lightning bolt is 28 (8d6) so it is doing 56 damage per round. However, there are two 4th level spell slots, and the CR guidelines use the most efficient damage dealing possible. So two rounds do 65 damage for an average of 62 damage. This puts offensive CR at 9 -1 for the low save DC for an offensive CR of 8.

You can go up to 84 (13d8 + 26) hit points. The Defensive CR would start at 1 and go up to 4. The average is CR 6.

Crud. Well, I might just go with a CR of 5 for him.

For resistances and immunities, even immunity to poison is enough to kick in the immunity multiplier.

Really? Ugh.

Cold and fire should probably count in the calculations for effective hp.

OK.

I only got an average of 83 DPR, but I may have missed something.

1 round of cone of cold against three targets is 36 * 3 - 108. Two rounds of [x] against two targets equals 17 * 2 *2 = 68. 108 + 68 = 176 / 3 = 58. I'm then supposed to add the damage from her freezing aura (5), any legendary actions (one deals 20), and lair actions (one deals 5). So that's 58 + 30 = 88.

Her overall CR is 10 now. I'll have to downgrade her defences a bit. The PCs will only be 5th level when they face her. Either that, or I'll have to let them level up to 6th level before they take her on.

Spellcasters are definitely the hardest to figure out.

Tell me about it!

The Abjurer's Armor and Ice Armor in Legacy of the Crystal Shard seem to be keyed to half of the NPCs hit points, but you can choose whatever number you want, and 24 is fine.

I dumped Gant's Abjurer's Armor when I turned him into an Enchanter, but I've kept Hedrun's ice armor. 24 is half - I've included it in the total of 73. (So her actual HP are 49.)

For Hedrun's Ice Darts and Ice Spear, I used magic missile and melf's acid arrow with cold damage. You might also like to take a look at ice storm. With Hedrun's immunity to cold and difficult terrain, she could drop that in the room and walk through unimpeded and pick off PCs one at a time as they are lost in the storm.

I dropped the ice darts altogether, but I've kept ice spear, although I'm not sure she'll actually use it. I had ice storm in her repertoire at first, but it was making her OCR too high, so I dropped it.