Monster creation and conversion questions

[Yora]

I am looking at the guidelines for monster creation in the DMG and when I look at the monsters in the MM, they all have only half as many hit points as the DMG recommends.

Now the DMG also says that you should average the appropriate CR for offense and defense, and that several resistances and immunities increase the effective hp a creature has by 50 or 100%. But that still doesn't seem to account for why the hp in the MM are so much lower.

Is there any reason for this that I have not spotted yet, or is the table in the DMG simply wrong?

[Ninja_Prawn]

Although there are a few monsters in the MM whose CRs don't line up with the guidelines in the DMG, the vast majority of them do. AC (which includes flight and magic resistance) makes a big difference, as do things like Legendary Resistance and multiple damage resistances. Anything that lets you Hide as a bonus action (like goblins can) counts as +4 AC, so that's a pretty big deal (it's effectively +1 CR).

Which monsters are you looking at in particular? We can run through a few of them step-by-step.

[Gastronomie]

This is a pretty common trend that seems bizarre on first glance but actually is not.

Let's take the Balor for example. Whereas a CR 19 monster should have 341-355 HP, the CR 19 Balor has only 262 HP. Its AC is the same as the suggested number (19), and looking at just these info, it seems the Balor is a squishy opponent. But in fact, that's far from the truth. Why is this?

To begin, the Balor has resistance to cold, lightning, and nonmagical weapon damage, and immunity to fire and poison damage. Most damaging spells are of cold, lightning or fire-type damage, and anyone using magical weapons to engage in melee with the Balor must take damage from its Fiery Aura ability. 3d6 backfiring damage per hit (and at the start of the Balor's every turn) is not an ignorable amount - for instance, a level 20 Fighter has to take 15d6 (average 52) fire damage per round by just standing next to the Balor and attacking him four times.

Next, the Balor is extremely sturdy against magical debuffs, with Magical Resistance on top of amazing saving throws (CON +12, WIS +9). The only common saving throw it sucks at is DEX (+2), but as aaforementioned, most blasting spells deal Fire, Cold or Lightning-type damage, meaning most magical AoEs are near useless against this thing anyways.

And to boot, the Balor can also teleport as an action (this will be used more for offense than for defense, though).

If the Balor had 341-355 HP on top of everything listed above, it would be a terribly overpowered monster. They balanced it out by giving it lower HP (it's still really sturdy, since it halves a lot of the attacks hurled at it, and ignores many others).

[Yora]

For example the standard orc. AC matches the recommendation for CR 1/2, damage is just on the border between CR 1/2 and 1. Attack bonus is +2 higher, but hp is only 15 compared to the recommended 50-70.

The real oddity is that seemingly every creature has much higher offense than recommended on the chart and much lower defense. Even if the two do even out, why not make the table so that the offense column is shifted two rows up and the defense column two rows down?
It might still roughly work out in the end, but that'd be a really weird way to construct a table.

[Tanarii]

Orc:
Defense: 15 hps AC 13 = CR 1/8
Offense: 9 dmg +5 to hit = CR 1 for damage, goes up to CR 2 for bonus to hit being 2 pts higher.
Total CR is 1/8 averaged with 2, or 1/2. (Averaging in this case means 2 steps up from 1/8 and 2 steps down from 2.)

Looks spot on to me.

Yes, most monsters have high offensive CR and low defensive CR. Yes it's a little weird they didn't just make that the baseline on their tables.

[Ninja_Prawn]

So, the orc has 15 HP at AC 13. DCR 1/8. It deals 9+2 (for Aggressive) @ +5. OCR 2.

2.125/2=1... So actually the orc may be underrated. They probably docked it a point because it's so flimsy.

The trend of OCR>DCR only holds at low CRs though. Creatures with multiple resistances and especially those with legendary resistance tend to be more 'balanced' between attack and defense.

Edit: aww, ninja'd. Yeah, you're probably right that it's about 'steps' rather than arithmetic.

[Kryx]

Keep in mind that the Monster Manual creatures were created before these guidlines were.

A good number of monsters have incorrect CR as a result. It's rather unfortunate.

[Inglorin]

A good number of monsters have incorrect CR as a result. It's rather unfortunate.

Yeah, you keep mentioning this. Do you have a list which monsters don't conform to the DMG guidelines? I'd like to check them and mark them in my MM...

[Tanarii]

The trend of OCR>DCR only holds at low CRs though. Creatures with multiple resistances and especially those with legendary resistance tend to be more 'balanced' between attack and defense.Really? I almost never have a need for high CR creatures. As usual my opinions on anything 5e is based on low level play (ie 1-10).

[Kryx]

I don't have a complete list, no. http://rpg.stackexchange.com/questions/69206/ogre-cr-calculation-is-it-wrong-or-am-i-missing-something discusses this a bit.
I think the Ogre is a great example. The CR math shows CR 1 1/8, but his CR is fudged to CR 2 because it can 1 shot a level 1 character. I'd argue then that the system to calculate CR is flawed if this simple case can't produce an accurate CR. There is nothing complex or out of line for an ogre - its damage is very straight forward.

But "playtesting".. blah blah blah. Either make CR usable or don't. I'm sure others would love to rant about CR more than I would. I'm well into the apathy phase.

[Yora]

I've started to convert my homebrew monsters to fifth edition and got pretty far simply with reskinning of existing monsters. (About 45 out of 90.) Now it's starting to get a bit more challenging with creatures that don't really have anything directly compatible in the MM.

Are there any other resources where people have converted large numbers of old monsters to 5th edition? That might be quite helpful to have some guidelines and a pool of additional special abilities to copy.

[Ninja_Prawn]

Really? I almost never have a need for high CR creatures. As usual my opinions on anything 5e is based on low level play (ie 1-10).

Oh, me too. Most of my experience with high-level stuff comes from all the homebrewing I do. For example, I recently made a 5e version of the Shivhad from Frostburn (not available to the public unfortunately; it'll be for MFoV subscribers only). I built it freestyle, aiming to capture the spirit of the original with a CR between 20 and 25. It ended up with DCR 22 and OCR 24, for an average of 23. I generally find big boss monsters end up like that, with fairly close offense and defense levels. Legendary resistance is a huge factor; I really can't overstate the impact it has.

[Yora]

One of the slightly more unusual creatures I am working on is this swamp beast. Basically a huge octopus that can grasp multiple opponents at the same time.
Using the giant octopus (http://5thsrd.org/gamemaster_rules/monsters/giant_octopus/) as a base I made this:

Swamp Beast
Huge monstrosity
Armor Class 14 (natural armor)
Hit Points 151 (15d12+54)
Speed 10 ft., swim 40 ft.
Str 21 (+5), Dex 13 (+1), Con 17 (+3), Int 4 (-3), Wis 10 (+0), Cha 4 (-3)
Damage Resistances bludgeoning
Condition Immunities prone
Skills Perception +5, Stealth +61
Senses blindsight 30 ft., passive Perception 15
Languages -
Challenge 6 (3,200 XP)4
Hold Breath: While out of water, the swamp beast can hold its breath for 1 hour.
Water Breathing: The swamp beast can breathe only underwater.
Actions
Multiattack: The swamp beast makes two attacks with its tentacles. It can continue to hold grappled creatures without requiring a new attack.
Tentacles: Melee Weapon Attack: +8 to hit, reach 20 ft., one target. Hit: 16 (2d10+5) bludgeoning damage. If the target is a creature, it is grappled (escape DC 17)2. The swamp beast has six tentacles, each of which can grapple only one target.3


1.) Where do these numbers come from? The giant octopus is CR 1 so it's proficiency bonus would be +2. Is there a reason it has Perception is +4 or is that arbitrary?
2.) DCs are 8 + proficiency bonus + relevant ability modifiers. If you'd add both Strength and Dexterity from the giant octopus it'd still only be 14. Is there another factor is that an arbitrary adjustment uniqe to the giant octopus?
3.) Is there a creature that does something similar that I could copy? (Giant crab can grapple two opponents though it has only one attack per round.) How would this affect effective damage per round? I'd say the swamp beast can only make two attacks per round but keep holding four more in a grapple that it attacked in previous rounds. Does that seem a good solution?
4.) Does CR 6 seems right for this?

[Ninja_Prawn]

One of the slightly more unusual creatures I am working on is this swamp beast. Basically a huge octopus that can grasp multiple opponents at the same time.
Using the giant octopus (http://5thsrd.org/gamemaster_rules/monsters/giant_octopus/) as a base I made this:

Swamp Beast
Huge monstrosity
Armor Class 14 (natural armor)
Hit Points 151 (15d12+54)
Speed 10 ft., swim 40 ft.
Str 21 (+5), Dex 13 (+1), Con 17 (+3), Int 4 (-3), Wis 10 (+0), Cha 4 (-3)
Damage Resistances bludgeoning
Condition Immunities prone
Skills Perception +5, Stealth +61
Senses blindsight 30 ft., passive Perception 15
Languages -
Challenge 6 (3,200 XP)4
Hold Breath: While out of water, the swamp beast can hold its breath for 1 hour.
Water Breathing: The swamp beast can breathe only underwater.
Actions
Multiattack: The swamp beast makes two attacks with its tentacles. It can continue to hold grappled creatures without requiring a new attack.
Tentacles: Melee Weapon Attack: +8 to hit, reach 20 ft., one target. Hit: 16 (2d10+5) bludgeoning damage. If the target is a creature, it is grappled (escape DC 17)2. The swamp beast has six tentacles, each of which can grapple only one target.3


1.) Where do these numbers come from? The giant octopus is CR 1 so it's proficiency bonus would be +2. Is there a reason it has Perception is +4 or is that arbitrary?
2.) DCs are 8 + proficiency bonus + relevant ability modifiers. If you'd add both Strength and Dexterity from the giant octopus it'd still only be 14. Is there another factor is that an arbitrary adjustment uniqe to the giant octopus?
3.) Is there a creature that does something similar that I could copy? (Giant crab can grapple two opponents though it has only one attack per round.) How would this affect effective damage per round? I'd say the swamp beast can only make two attacks per round but keep holding four more in a grapple that it attacked in previous rounds. Does that seem a good solution?
4.) Does CR 6 seems right for this?

1. A lot of monsters have Expertise (like the Rogue), particularly in perception and stealth. It helps prevent stealthy PCs from effortlessly killing everything.

2. I... have no idea where the GO's 16 comes from. It could be an error. At a wild guess, it could be 8 + prof + Con mod (11) + 5 to represent a built-in advantage for having multiple tentacles?

3. Maybe check out the Roper?

4. Yes, I think so.

[Yora]

Oh yeah, the roper is exactly what I need. :smallsigh:

Actually, I might just reskin the roper and make it a bit bigger. This is right what I had in mind with the creature.