D&D 5E Custom Creature Balance Assessment

[chuckyp]

Hi,
I'm running a home game and have been able to pull what I need from the MM but have to design a couple of custom monsters that can't use a re-skinned monster from the book and I'm concerned about properly balancing them. I've tried the DMG creature creator section and the results always seem to be off from the book's standards. So I figured I'd throw this out there. The party is Lvl 6 (Cleric, Paladin, Fighter, Sorcerer) and I was planning on throwing four or five of these guys (evil doctor types) at them during an encounter. Does this seem level appropriate? I'm a little worried about the paralysis possibly being too strong since that means auto crits that even with low damage weapons can add up fast so I tried to balance it with limited uses. So I submit to the wisdom of the forum. Your thoughts?

Surgeon
AC 14 (no armor)
HP 45
Speed 30

STR 12
DEX 18
CON 13
INT 14
WIS 15
CHA 11
Saving Throws: Dex +7, Wis +5
Skills: Investigation +5, Medicine +5, Perception +5
Senses: Darkvision, Passive Perception 15

Actions:
Multiattack. The Surgeon makes three melee attacks using any combination of its syringes and its implement (scalpel/dagger) or (bonesaw/scimitar)

Syringe- anesthetic (poison). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 1 piercing damage and (2d6+2) poison damage. The target must succeed on a DC 10 (+2 for each previously successful injection, i.e. 10, 12, 14, etc.) Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

The Surgeon may make four Syringe attacks before having to refill its vials, which takes one action and requires it to be adjacent to a well capable of dispensing the poison.

Scalpel (dagger). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 1d4+4 piercing damage.

Bonesaw (scimitar). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 1d6+4 slashing damage.

 

[Bitbrain]

I'd be more worried about if he's underpowered. A 4 man party of that level and those classes, even if there are that many of these guys, will probably wipe the floor with them.

 

[chuckyp]

Ok, so suggestions for improvement? More HP? They have a high to hit bonus so I expected that there's going to be at least one or two paralyzed PCs each round, especially with the stacking save DC as the poison builds up in their systems, which would limit their fighting effectiveness as a group and keep them more defensive...

 

[Capn Charlie]

Accurate attacks to hit consistently, resistance to most AOE spells and crowd control in the form of high dex and wis saves, lower AC and hp along with modest damage, paired with a good debuff effect... seems good. I'd throw a wave of them at the party, then have a second wave come in if the party is having too easy of a time with them, maybe with a few Orderlies (using the Thug statblock).

 

[Quickleaf]

[MENTION=6865886]chuckyp[/MENTION] The DMG monster toolkit section doesn't address how giving a monster the power of paralyzation affects its CR.

Instead, you need to reverse engineer a simple lower CR monster with paralysis: the Carrion Crawler.

DMG Analysis of Carrion Crawler (CR 2)

Defense CR = 1/2

based on HP 51 & AC 13, conferring with DMG pg. 274

Offense CR = 3 (we should expect this to be 3 or 4, based on the Carrion Crawler's CR 2)

Bite +4 attack, 7 damage
Tentacles +8 attack, 4 damage, DC 13 save or poisoned/paralyzed, but target can re-test save at end of each of target's turn

So it deals a total of 11 damage. But what about its goofy attack bonus difference?

For the purposes of determining its average attack bonus, I'm treating the Bite as worth 64% of its damage and the Tentacles as worth 36% o its damage, therefore its "average" attack can be calculated as...

(0.64)4 + (0.36)8 = 3.84 + 2.88 = 6.72 rounded up to 7

So its "average" attack bonus is about +7.

Based on the chart on DMG pg. 274, this puts its Offense CR at 3 (or maybe more accurately about 2.5).

Total CR
(0.5 + 3) / 2 = 1.75

So it looks like from a straight numbers game that all the Carrion Crawler's form of paralyzation (similar to your Surgeon's) really adds up to in terms of CR is swaying which way the Offense CR rounds (i.e. round up).

Next Step
Your next step would be to calculate your Surgeon's Offense CR based on a simulate 3 rounds of combat, probably doing something like...
Round 1. Syringe/Scalpel/Bonesaw
Round 2. Syringe/Scalpel/Bonesaw
Round 3. Syringe/Scalpel/Bonesaw

Surgeon
AC 14 (no armor)
HP 45
Speed 30

STR 12
DEX 18
CON 13
INT 14
WIS 15
CHA 11
Saving Throws: Dex +7, Wis +5
Skills: Investigation +5, Medicine +5, Perception +5
Senses: Darkvision, Passive Perception 15

Actions:
Multiattack. The Surgeon makes three melee attacks using any combination of its syringes and its implement (scalpel/dagger) or (bonesaw/scimitar)

Syringe- anesthetic (poison). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 1 piercing damage and (2d6+2) poison damage. The target must succeed on a DC 10 (+2 for each previously successful injection, i.e. 10, 12, 14, etc.) Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

The Surgeon may make four Syringe attacks before having to refill its vials, which takes one action and requires it to be adjacent to a well capable of dispensing the poison.

Scalpel (dagger). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 1d4+4 piercing damage.

Bonesaw (scimitar). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 1d6+4 slashing damage.

DMG Analysis of your Surgeon

Defense CR = 1/2

Technically this is CR 1/4 according to the DMG, but I could see this being CR 1/2 because his HP are at the upper edge of the CR 1/4 threshold (36-45), and his AC is 14 (vs 13), and has two proficient saves (which the DMG doesn't normally tabulate, but you can argue are worth +1 AC especially since DEX and WIS are the most common saves in the game). Personally, for that reason, I consider its Defense CR to be 1/2

Offense CR = 4

Total damage 10 (syringe) + 6 (scalpel) + 7 (bonesaw) = 23

This puts him at Offense CR 3 so far.

His attack bonus of +7, however, bumps him up one step on the DMG chart to Offense CR 4.

Total CR = 3

(0.5 + 4) / 2 = 2.25

Normally, I would round down to CR 2. However, because of the Surgeon's paralyzation ability (and how that synchronizes with other Surgeons to potentially skyrocket the save DC vs. its paralyzation well above the Carrion Crawler), I am inclined to round up to CR 3.

Encounter Building

And finally, about how many Surgeons would be a good fight for your party of four 6th-level PCs?

Without knowing your party, I can only go off the DMG guidelines, which suggest that 3 Surgeons would make for a Hard fight, while 4 Surgeons would make for a Deadly fight.

 

[chuckyp]

Thanks for the input, especially the breakdown of the DMG creator section. The party demolished five CR3s in their first fight so I want to throw something hard at them to shake them up but not outright flatline them since this encounter is specifically intended to drive the plot. I've found that CRs seem to heavily favor the PCs.

 

[Lanliss]

For a surgeon, shouldn't he have proficiency in Slight of Hand, because of his delicate work?