How to Create an Epic Monster | New Rules for Fifth Edition (BroadSword Preview)

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How to Create an Epic Monster

More than a few people have commented on how some of the high-level Fifth Edition monsters can be somewhat lacking. For example, everyone’s favorite city-crushing turtle monster, the tarrasque, leaves a lot to be desired in its Fifth Edition form. This article goes into detail on how to create epic, multi-component creatures for your Fifth Edition campaigns.

The Limitations of CR 30

As a CR 30 monster in Fifth Edition, a creature can only have so much for its stats and ability scores. Looking at the Monster Statistics by Challenge Rating table (DMG), a CR 30 monster has the equivalent of an AC 19, 806 – 850 hit points, a +14 to hit (or DC 23 save), and deals 303 – 320 damage per turn.

Are those numbers insane? Totally. But for a completely rested, carefully equipped and prepared party of 20th-level heroes, that’s just another day at work.

Referencing the Epic Solo Monster Challenge Rating table, we know that a group of seven 12th-level characters can go toe-to-toe against a CR 30 creature (with enough advanced notice, of course). In fact, a group of seven 12th-level characters can reasonably take on 280,000 adjusted XP per day according to the Adventuring Day XP table (DMG), almost twice as much provided by a single CR 30 creature.

In fact, such an encounter could be two monsters of CR 29, three CR 24s, four CR 23s, five CR 21s, six CR 21s, seven CR 18s, eight CR 17s, nine CR 16s, ten CR 15s, and so on.

Creating One Monster from Many

Okay, since we understand the basics of epic encounters, it’s simply a matter of creating a single, devastating monster. And the best way to do this is to take the monster and make it into a bunch of “small monsters.” Thankfully, the recently released “of ships and the sea” rules for Fifth Edition gives us the perfect blueprint for doing just that.

With the ship rules, all of the ships are divided into different components, each of which comprises multiple objects: the hull, control, movement, and weapons. Those ship components can even have special rules described in the stat block. Huge, epic monsters work the same way, especially if you want something that’s bigger than “gargantuan.”

Consider something like Great Cthulhu. Cthulhu has his elephantine body; this is his “hull.” His head controls his body and every other part. He can move by walking or by flying. And for weapons, he’s got tentacles, claws, and a whole bunch of special attacks. Instead of slapping a CR 30 on everyone’s favorite Great Old One and calling it a day, we can take Cthulhu’s separate components and turn him into an epic challenge.

Building an Epic Challenge on a Budget

If you know the size of the party and the amount of adventuring day XP they can handle, you can use those numbers to reverse engineer the epic monsters. Here is how to come up with that number.

  1. First, determine the amount of adjusted XP per Day per Character (DMG, chapter 3). Multiply that number by the total number of characters in the party. For example, a party of four 12th-level characters can handle a total of 46,000 adjusted XP per day.
  2. Next, decide how many components you want your epic monster to have. In the Cthulhu example above, Cthulhu had six components: body, head, claws, feet, wings, and tentacles.
  3. Treat each component as its own “monster” and determine the challenge rating for each piece using the Enoucnter Difficulty Multipliers table (DMG, chapter 3). Cthulhu has six components, so the encounter multiplier will be x2.
  4. Divide the total adjusted XP per day by the encounter multiplier and the total number of components. This is the experience points rewarded per component. Since Cthulhu has six components and an encounter multiplier of x2, each component will need to be worth 3,833 experience.
  5. Pick the components’ challenge rating based on the experience reward. With our Cthulhu example, each component is worth 3,833 unadjusted experience. That’s roughly a CR 8.
  6. Double-check your math. When dealing with numbers like these, you want to make sure you’re not too far off. A miscalculation can result in a TPK for sure. A CR 9 monster is worth 3,900 XP. Six CR 8 monsters would be worth a total of 23,400 experience. Using the encounter multiplier of x2 for six creatures, that’s a total adjusted encounter XP of 46,800. Divide that four ways, and we have 11,700 adjusted XP per day per character. Perfect for a group of four 12th-level characters.

How to Build Each Component

Now that we have the math out of the way, it’s just a matter of building the creatures. According to the “Creating a Monster” rules (DMG, chapter 9), we know roughly what monster statistics by challenge rating should equal. For example, a CR 8 monster has an AC of 16, 176 – 190 hit points, a +7 attack bonus, and deals 51 – 56 damage per round.

Remember that certain features and abilities such as flying or damage immunities can affect these values.

Here are examples of how to build each component.

Cthulhu’s Basic Stats

First, we need to have Cthulhu’s basic stats. These are the stats that are common for each component. Just like a typical monster stat block, it lists his size, type, ability scores, traits, and features.

Here is a way that I might build out our six CR 8 component Cthulhu’s basic stats.

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Great Cthulhu

Huge aberration (Great Old One), chaotic evil (25 feet tall)

Travel Pace 8 miles per hour (192 miles per day)

Abilities Str 25 (+7), Dex 12 (+1), Con 23 (+6), Int 20 (+5), Wis 20 (+5), Cha 20 (+5)

Saving Throws Int +8, Wis +8, Cha +8

Skills Arcana +8, Insight +8, Religion +8, Perception +8

Damage Resistances acid, cold, fire, lightning, poison, necrotic, thunder; bludgeoning, piercing, and slashing from nonmagical weapons

Condition Immunities charmed, frightened, paralyzed, petrified, poisoned, stunned

Senses truesight 120 feet, passive Perception 36

Languages all, telepathy 500 feet

Challenge special (23,400 XP)

Immutable Form. Cthulhu is immune to any spell or effect that would alter his form.

Magic Resistance. Cthulhu has advantage on saving throws against all other spells and magical effects.

Regeneration. Each of Cthulhu’s components regains 10 hit points at the start of his turn. If a component takes radiant damage, this trait doesn’t function at the start of Cthulhu’s next turn. Cthulhu dies only if his head and his body has 0 hit points at the start of his turn and doesn’t regenerate.

Siege Monster. Cthulhu’s attacks deal double damage to objects and structures.

Unspeakable Presence. Any creature that starts its turn within 100 feet of Cthulhu and is aware of him must make a DC 16 Wisdom saving throw. On a failed saving throw, a creature takes 11 (2d10) psychic damage and becomes frightened for 1 minute. A creature can repeat its saving throw at the end of each of its turns, ending the effect on itself with a success. A creature that passes its saving throw or the effect ends for it is immune to Cthulhu’s Unspeakable Presence for 24 hours.


Cthulhu’s Actions

Next, we to determine Cthulhu’s action allowance. As a multi-component epic threat, Cthulhu will have a mix of regular actions and legendary actions. To avoid confusion, it’s best to put all those elements directly into his stat block. Then, we offer up actions that make sense for him to take, similar to the way ships operate.

This is the language I use for his actions and legendary actions. I’ve given Cthulhu the ability to make up to six attacks per round, three on his turn, and three as legendary actions.

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Actions and Legendary Actions

On his turn, Cthulhu can take 3 actions, choosing from the options below.

In addition, Cthulhu can take 3 legendary actions, choosing from the same options. Only one legendary action can be used at a time and only at the end of another creature’s turn. Cthulhu regains spent legendary actions at the start of his turn.

Claws. Cthulhu uses his body to attack with his claws.

Heal. Cthulhu uses his body to heal himself.

Magical Attack (Costs 3 Actions, 1/Round). Cthulhu uses his head to make a magical attack.

Move. Cthulhu uses his body to move with his feet or his wings.

Non-Attack Action. Cthulhu uses his head to take the Disengage, Dodge, Help, Hide, Search, or Use an Object action.

Spell. Cthulhu uses his head to cast one of his innate spells.

Tentacles. Cthulhu uses his head to attack with up to two of his tentacles.


Cthulhu’s Body

Next, we use Cthulhu’s body to set the biggest target for his challengers. This acts similar to a ship’s hull, establishing the majority of Cthulhu’s hit points and AC. Because the body won’t have any attacks of its own, we’ll need to make the hit points and AC disproportionate to the rest of his form.

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Armor Class 18 (natural armor)

Hit Points 200 (damage threshold 20)

Heal: One of Cthulhu’s components regains 25 hit points.

Movement: Move up to the speed of one of Cthulhu’s movement components.


Cthulhu’s Head

The component that controls Cthulhu’s movements is his head. In addition, it acts as a weapon, too, allowing him to make attacks with spells and magical abilities.

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Control & Weapons: Head

Armor Class 16 (natural armor)

Hit Points 125 (damage threshold 10)

Senses. If Cthulhu’s head is reduced to 0 hit points, he is blinded and deafened.

Innate Spellcasting: Cthulhu’s innate spellcasting ability is Intelligence (spell save DC 16). He can innately cast the following spells, requiring no components:

  • At will: detect evil and good, detect magic, sending,
  • 1/Day: control watercontrol weatherplane shift (self only), teleport

Magical Attack: Mind Blast: Cthulhu emits a torrent of psychic energy in a 90-foot cone. Each creature in the area must make a successful DC 16 Intelligence saving throw or take 27 (4d10 + 5) psychic damage. 


Cthulhu’s Movement Components

Now we need a way for our epic Cthulhu challenge to get around town. We’ve given him two such components, detailed below.

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Movement: Feet

Armor Class 16 (natural armor)

Hit Points 100 (threshold 10)

Speed (land) 40 ft.

Rampage. While moving, Cthulhu can enter a creature’s space and stop there. The first time he enters a creature’s space on his turn, that creature must make a DC 16 Strength or Dexterity saving throw (target’s choice). On a failed saving throw, the creature is knocked prone and takes 16 (2d10 + 5) bludgeoning damage plus 11 (2d10) necrotic damage. On a successful saving throw, a creature takes half as much damage and isn’t knocked prone.

Movement: Wings

Armor Class 16 (natural armor)

Hit Points 100 (threshold 10)

Speed (air) 60 ft.

Wing Blast. Whenever Cthulhu moves using his wings, each creature within 15 feet of Cthulhu at the start of his movement must succeed on a DC 16 Dexterity saving throw or take 27 (4d10 + 5) bludgeoning damage and be knocked prone.


Cthulhu’s Main Weapons

In addition to the magical abilities of his head, Cthulhu can make attacks with his claws and his tentacles, as detailed below.

[su_note note_color=”#fafafa”]

Weapons: Claws (2)

Armor Class 16 (natural armor)

Hit Points 50

Melee Weapon Attack: +8 to hit, reach 15 ft., one target. Hit: 16 (2d8 + 7) slashing damage.

Weapons: Tentacles (10)

Armor Class 16 (natural armor)

Hit Points 25

Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 12 (1d10 + 7) bludgeoning damage plus 9 (1d10 + 5) psychic damage plus 5 (1d10) necrotic damage. If the target is a creature, it is grappled (escape DC 17). Until the grapple ends, the target is restrained and takes 9 (1d10 + 5) psychic damage plus 5 (5d10) necrotic damage at the start of each of its turns and Cthulhu can’t use the same tentacle on another target.


Cthulhu Rises!

And that’s pretty much it. You now have a massive, unspeakable, eldritch horror stomping around beating up your characters. If they destroy Cthulhu’s head, he can still thrash around with his claws and wings. If they destroy his body, he can still deal damage with his spells and magical effects, but can’t heal himself beyond his regeneration. Good times!

Now that you have rules for creating epic monsters, what sort of horrible creations will you create? Ω

PS I realize that this version of Cthulhu may be seen as somewhat “weak.” If you prefer, consider this a “star spawn.” And for a much tougher Cthulhu, check out

3 thoughts on “How to Create an Epic Monster | New Rules for Fifth Edition (BroadSword Preview)

  1. How would legendary resistances work with this method of monster creation (e.g. would Cthulhu only have three legendary resistances total, or one per component, or even three per component)?

  2. How would legendary resistances work with these kinds of creatures (e.g. would Cthulhu have three legendary resistances total, one per component, three per component, etc.)? Sorry if you see this comment twice, this is the first time I’m doing so here.

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