- Name. Myrkridia. That was easy!
- Size. Medium. Mmm, now I'm looking forward to writing the other creature even more...
- Type. Huh. The obvious answer here is Humanoid, but with that backstory of banishment I could kinda justify Fiend. My other option is Monstrosity. If you can tell me why a lizardfolk is humanoid but a yuan-ti malison is a monstrosity, I want to hear it. Anyway, I'm going with Monstrosity, because the lore really emphasizes the horror elements of these creatures.
- Alignment. Well, I hate alignment rules, but fine, whatever. Chaotic Evil.
- Ability Scores and Modifiers. Hmm. Picking this before I've set the CR in this process seems off to me. Okay, if CR 3 werewolves have Str 15, Dex 13, Con 14, Int 10, Wis 11, Cha 10, I will peg the Myrkridia at Str 16, Dex 14, Con 14, Int 10, Wis 11, Cha 10.
- Expected Challenge Rating. I decided this before I even cracked open the book! CR 6, so Proficiency Bonus +3.
- Armor Class. Myrkridia rely on natural armor and Dexterity for defense, so I'll use the table. CR 6 grants AC 15. I have a feeling I'll edge off on this later on, but we'll see.
- Hit Points. I don't have a preconceived notion of how many Hit Dice I want the Myrkridia to have, so I'll use the table again... giving it a whopping 146-160 hit points. Well, being really hard to kill is on-theme at least.
- Damage Vulnerabilities, Resistances, and Immunities. I don't think Myrkridia are known to be immune to anything, and considering that some of the other baddies in the Myth series most certainly are immune to things, I can assume it would be well-documented. This step is where things start to get complicated, so I'm happy I can blow past it.
- Attack Bonus. I get the same result here whether I use the table or calculate based on what I've established: +6. Sounds fine.
- Damage. I won't lie, I get a gleam of malicious glee in my eye when I reach this item. Because Myrkridia use claws and a bite, I'm using the table to determine target damage output - I don't have any other preconceptions about what those die values should be. CR 6 grants... drumroll... an average of 39-44 damage per round. Assuming its 146-160 hit points keep it alive for a few rounds, a single Myrkridia can put a serious hurt on an enemy's front line, and God help you if it reaches your chewy clothy center.
- Save DCs. I don't know that these will matter, per se, but sure. The Calculate the DC method gives me DC 14; the table gives me DC 15. We'll see if this even comes up.
- Special Traits, Actions, and Reactions. There's room for additions here, but the baseline representation of Myrkridia in Myth requires a Flesh Golem-style Berserk trait. This one isn't rated on pp. 280-281, but it doesn't change damage output or defenses, just the Myrkridia's IFF system, so to speak. No CR adjustment, and it needs to be tweaked from the Flesh Golem trait. Anyway, I'll come back to this when I'm writing the stat block.
- Speed. Within Myth, Myrkridia are noted for their great speed. This is talking about both their attack animation speed (which I'll be covering by splitting their expected damage per round into several attacks) and their walking speed. Speed higher than 30 ft. doesn't change CR unless they're flyers (followed by several other conditionals), so I can set Speed to 45 feet. Arbitrary, but slightly faster than someone with the Mobile feat; equivalent to a 6th-level human Monk. Fine, whatever.
- Saving Throw Bonuses. I don't know that Myth has an obvious cognate for saving throws, though that foot speed means that Myrkridia are going to be harder than many Dark units to target with dwarven explosives. I'm good with giving the Myrkridia proficiency in Dexterity saving throws to reflect this.
- Final Challenge Rating. Well, I haven't actually done anything that requires a modification of CR.
- Skill Bonuses. Athletics seems right to me here - I don't think one gets away from a Myrkridia by trying to out-climb or out-swim it. I don't know that any other skills are indicated in Myth, but maybe I'll toss them Arcana proficiency to reflect their cultural obsession with giant mounds of skulls (since the Myrkridian Giants enchant skulls to explode).
- Condition Immunities. There aren't any conditions on the D&D list found in Myth, to my knowledge, and I'm always looking for reasons not to hand out immunities. That was easy.
- Senses. If Myrkridia have any unique senses, we don't know about them from the game's lore. Since I gave them a Wisdom of 11, their Passive Perception is 10.
- Languages. According to the lore, they can understand Common, and we don't know whether or not they can speak it. They also have their own language, which the rare Myrkridia Pack-Mages presumably use to cast their spells. Works for me.
Myrkridia
Medium monstrosity, chaotic evil
Armor Class 15 (natural armor)
Hit Points 156 (24d8 + 48)
Speed 45 ft.
Str 16 Dex 14 Con 14 Int 10 Wis 11 Cha 10
Saving Throws Dexterity +5
Skills Athletics +6, Arcana +3
Senses Passive Perception 10
Languages Common, Myrkridian
Challenge 6 (2,300 XP)
Berserk. Whenever a Myrkridia begins its turn below 40 hit points, it directs its attacks against the nearest creature, regardless of whether that creature is an enemy or an ally. If it can perceive more than one creature that is equally near to it, randomly determine which creature it attacks. For purposes of game effects, it regards all creatures as enemies for as long as it is berserk. At the end of any turn that it has not dealt or received damage, it can attempt a Charisma saving throw against DC 12 to end its berserk state. If it takes damage again that results in the Myrkridia having fewer than 40 hit points, it goes berserk again.
Actions
Multiattack. The Myrkridia makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 20 (3d10 + 3) piercing damage.
Claws. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d8 + 3) slashing damage.
Design Notes
Um. These guys seem incredibly heinous to me, maybe a little more than I set out to make them - but these are just the numbers given, if you don't have a bunch of other traits getting involved to kind of "soak up" CR budget. Let me check some other CR 6 creatures and see how they look.
Chasme: Okay, spectacular damage output that reduces maximum hit points, plus its Drone ability, Magic Resistance, some damage resistances, et cetera and most certainly ad infernum... pretty good tradeoff for having just over half the predicted hit points for CR 6.
Wyvern: Damage output once again conforms perfectly to the model, but I can't figure out why its AC is two points low and its hit points are 36-50 points low. Maybe the designer is treating the reach of its attacks as a tangible benefit?
After creating the Myrkridia, I'm deeply grateful that the math of the system flows forth from the CR, rather than ending with a CR calculation as 3.x does. From the players' point of view, it doesn't matter that I've had to give this Medium creature 24 hit dice in order to give it enough hit points, but they do care that I've given it a respectable-but-not-dominating 14 Constitution. Many creatures in 3.x, but especially undead published late in the edition, jumped through some very strange hoops to have enough hit points and other traits to challenge the PCs appropriately.
Myrkridian Giant
Since I did 20-step creation for the Myrkridian, let's try the 4-step quick creation for the Myrkridian Giants. (I'd just be repeating myself for a lot of these steps, since the lore isn't that different.)
- Expected Challenge Rating. CR 12
- Basic Statistics. Proficiency bonus +4, AC 17, Hit Points 236-250, Attack Bonus +8, Damage Per Round 75-80 (!), Save DC 17.
- Adjust Statistics. I guess I'm pretty comfortable with those numbers. My main trouble is going to be setting Ability Scores, once I have to do that, because in this creation method, the numbers don't naturally proceed from the ability scores. (They don't in the other one either, strictly speaking, but there's some discussion of how to correct for ability scores doing something other than what you want.)
- Final Challenge Rating. Okay, this method is a bit too rushed. In all honesty, there's a key step that it's kind of ignoring - the one where you figure out to turn that damage-per-round range into specific attacks. That may be unfair; what I mean to say is that that's the step that requires some figuring, and leaving it off the checklist is a bit misleading. The damage calculation for the Myrkridian Giant is more complicated, because I'm planning to treat the exploding skulls as fireballs.
Myrkridian Giant
Large monstrosity, chaotic evil
Armor Class 17 (natural armor)
Hit Points 246 (29d10 + 87)
Speed 55 ft.
Str 19 Dex 16 Con 16 Int 10 Wis 12 Cha 10
Saving Throws Dexterity +7
Skills Athletics +8, Arcana +4
Senses Passive Perception 11
Languages Common, Myrkridian
Challenge Rating 12 (8,400 XP)
Berserk. Whenever a Myrkridian Giant begins its turn below 62 hit points, it directs its attacks against the nearest creature, regardless of whether that creature is an enemy or an ally. If it can perceive more than one creature that is equally near to it, randomly determine which creature it attacks. For purposes of game effects, it regards all creatures as enemies for as long as it is berserk. At the end of any turn that it has not dealt or received damage, it can attempt a Charisma saving throw against DC 12 to end its berserk state. If it takes damage again that results in the Myrkridian Giant having fewer than 62 hit points, it goes berserk again.
Actions
Multiattack. The Myrkridian Giant makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 37 (5d12 + 4) piercing damage.
Claws. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 21 (3d10 + 4) slashing damage.
Exploding Skull. A Myrkridian Giant carries 1d4 skulls, which explode when thrown. It can throw these skulls up to 150 feet. Each creature in a 20-foot-radius sphere must roll a Dexterity saving throw (DC 17). On a failed save, the target takes 11d6 fire damage, or half as much damage on a successful one. The exploding skull ignites flammable items that aren't being worn or carried.
Design Notes
As noted above, there aren't many CR 12 creatures to compare the Myrkridian Giant to, and two of them (the archmage and the arcanaloth) get their damage calculation from spellcasting. The erinyes uses weapons, but spends a lot of CR budget on defenses rather than raw damage output.
Since I've used the term "CR budget" a few times in this post, let me clarify for anyone who hasn't read the 5e DMG: this is a term of convenience for me, not an actual rules concept in building monsters. I'm talking about how a monster has an offensive CR and a defensive CR, you get its final CR by averaging the two, and offensive or defensive CR may be treated as one or more levels higher than they actually are if the creature possesses particular traits or combinations of defenses. Other than the note above about working out dice expressions that result in the right damage-per-round, this is overall less mathy than 3.x or 4e monster creation.
I can't yet attest to how the Myrkridia work in play - whether its total lack of traits, giving it very high normal defenses and damage output, are a benefit or a weakness. What it definitely does is make them less interesting as monsters - there aren't a lot of abilities that present theme here, so you've got to already know their lore to understand how to use them. I might want to change that, because even themes like "ravening monster from a mythic age" can be expressed with subtle details rather than just giving it bigger numbers. On the other hand, if I develop more of the creatures of Myth into 5e rules, they're likely to have more such traits, providing the Myrkridia some characterization through contrast.