A creature's challenge rating is the Dungeon Master's (DM's) indication of how difficult a particular monster or another enemy will be for their party. The official Dungeons & Dragons rules suggest that, unless the DM is really looking to throw a challenge out there, they should stick to using monsters who have a challenge rating that's approximately the same as their players' levels.
While no official rule says that monsters can't exceed a challenge rating of 30, there are no monsters that do. Since players generally don't go past level 20, this makes sense (that would be one hell of a challenge!). These monsters from the official Dungeons and Dragons rulebooks are among the toughest to beat in the franchise.
Updated October 2, 2022, by Gabrielle Huston: If you're looking for the toughest monsters in D&D, you'll find them here. This article now includes brand new monsters that rank among the most powerful in existence!
15 Astral Dreadnought - CR 21
- Challenge Rating: 21
- Size: Gargantuan
- Type: Monstrosity
- Alignment: Unaligned
- Homeland: Astral Plane
- Found In: Modenkainen's Tome Of Foes or Modenkainen Presents: Monsters of the Multiverse
This horrible creature extends to a significant length, since its lower half is actually akin to a snake's, with scales made of tough armored plates. Its upper body features one huge eye, capable of nullifying magic wherever it's pointed, and arms with pincers instead of hands. The Astral Dreadnought is named for its homeland, the Astral Plane, which is a plan of existence akin to purgatory — people from the Prime Material Plane reach it through spells, magical devices, or psionic abilities.
14 Zaratan - CR 22
- Challenge Rating: 22
- Size: Gargantuan
- Type: Elemental
- Alignment: Neutral
- Homeland: Zakhara
- Found In: Modenkainen's Tome Of Foes or Modenkainen Presents: Monsters of the Multiverse
One can't help but imagine the Pokemon Torterra when looking at the Zaratan. This beast is said to measure hundreds of feet in diameter and live for millennia. However, unlike the Torterra that appears on land (as in the Detective Pikachu movie), the Zaratan lives in the sea.
Unless it's sufficiently provoked, the Zaratan is passive and does not attack people (even if it notices them); it actually crawls up into its shell, just like one would expect from your average land turtle.
13 Ancient Green/Bronze Dragon - CR 22
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Ancient Green Dragon |
Ancient Bronze Dragon |
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Dragons are, of course, the most iconic enemy in Dungeons and Dragons. The Green Dragon is a chromatic dragon, a type known for being non-reflective and are generally somewhere on the evil side of the alignment chart. The Bronze Dragon, its counterpart, is a Metallic dragon, meaning its scales look akin to metal and usually fall on the good end of the alignment chart. They have a challenge rating of 22. Even though they fall on opposite ends of alignment, both these dragons are aggressive when threatened or challenged.
12 Lich (In Its Lair) - CR 22
- Challenge Rating: 22
- Size: Medium
- Type: Undead
- Alignment: Lawful Evil, Neutral Evil, Chaotic Evil
- Homeland: Prime Material Plane
- Found In: Monster Manual
Liches are a powerful kind of undead magic-user (usually a wizard, but they might also be a cleric or a sorcerer, under the right circumstances). They're nearly always on the evil end of the alignment chart, but exceptions do exist.
They were once people, like you and me, but embraced undeath so that they could live forever and continue to attain knowledge, a pursuit that consumed their mind until it was an obsession. Liches are significantly more powerful on their own turf: a lich outside its lair only has a challenge rating of 21.
11 Ancient Silver/Blue Dragon - CR 23
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Ancient Blue Dragon |
Ancient Silver Dragon |
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The Blue chromatic dragon and its metallic counterpart, the silver dragon, are slightly higher on the challenge rating scale, at 23. While blue dragons are infamous for the hallucinations they could induce on their enemies, silver dragons actually preferred to live among humans or elves. They would take a humanoid form and often live in the pursuit of knowledge. When in their dragon form, silver dragons preferred to live in snowy mountains. Meanwhile, blue dragons often inhabited arid deserts.
10 Empyrean - CR 23
- Challenge Rating: 23
- Size: Huge
- Type: Celestial
- Alignment: Chaotic Good or Neutral Evil
- Homeland: Upper Planes
- Found In: Monster Manual
The average D&D player won't ever have occasion to fight — or even meet — an Empyrean. These creatures are the children of gods from the Upper Planes, who are described as the manifestation of beauty. Empyreans are generally on the good side of the alignment chart. However, they can be corrupted. Occasionally, they might be exposed to the Lower Planes, or be cursed by an evil god; it's at this point that they are forced to enter the Prime Material Plane, no longer at home among the other gods on the Upper Planes.
9 Kraken - CR 23
- Challenge Rating: 23
- Size: Gargantuan
- Type: Monstrosity
- Alignment: Chaotic Evil
- Homeland: Oceans
- Found In: Monster Manual
Krakens are a common fantasy monster, depicted or mentioned by Pirates of the Caribbean, Moby-Dick, and Clash of the Titans (among many others). They have a huge number of octopus- or squid-like tentacles which crush ships and swallow their crew. In D&D, they're known as a reality of life on the ocean. It's even noted that a Kraken could destroy entire island societies and force the surviving humans to be its slaves, feeding, cleaning, and otherwise tending to the beast.
8 Ancient Red/Gold Dragon - CR 24
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Ancient Red Dragon |
Ancient Gold Dragon |
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The Red and Gold dragons are the most powerful of the metallic and chromatic dragon types. Red dragons bring to mind depictions of Smaug, from Tolkien's The Hobbit. They are fire-breathing monsters who hoard treasure with a fury unlike anything seen among mortal men.
Gold dragons may also remind players of Smaug, but only during the scene in the films where he emerges from Thorin's smoldering lake of liquid gold. These dragons are often described as majestic and are usually lawful good. They also breathe fire but prefer to stay reclusive in stone caverns, deep beneath the earth or in the mountains.
7 Marut - CR 25
- Challenge Rating: 25
- Size: Large
- Type: Construct
- Alignment: Lawful Neutral
- Homeland: Mechanus, Dweomerheart
- Found In: Modenkainen's Tome Of Foes or Modenkainen Presents: Monsters of the Multiverse
"Constructs" is a term used to denote any creature that's been created by another through non-natural means, such as animating objects. The Marut, unlike most other constructs, are actually intelligent — they were a type of "inevitables" created by a greater deity named Mystra, who was trying to fulfill her role of guarding all magic. Their alignment is true neutral, so a Marut will only fight in self-defense, to resolve a conflict, or if someone is trying to stop them from fulfilling their duties.
6 Archduke Zariel Of Avernus - CR 26
- Challenge Rating: 26
- Size: Medium
- Type: Fiend
- Alignment: Lawful Evil
- Homeland: Avernus
- Found In: Baldur's Gate: Descent into Avernus
Archduke Zariel is the ruler of Avernus, the first layer of the Nine Hells.
Once upon a time, she was an angel from the Seven Heavens of Mount Celestia. She believed that it was the responsibility of angels to destroy all Fiends and, as a result, protect the multiverse from the devastation caused by their wars. Against her orders, Zariel led troops into Avernus. She was swiftly defeated and only survived because Asmodeus (the overlord of the Nine Hells) sent creatures to recover her body after the battle. As a result, she gave in to her corruption and Hell's influence, becoming an archdevil and Asmodeus' champion.
5 Ral Tulkhesh - CR 28
- Challenge Rating: 28
- Size: Huge
- Type: Fiend
- Alignment: Neutral Evil
- Homeland: Eberron
- Found In: Eberron: Rising from the Last War
Long ago, the planet of Eberron was ruled by a race called the Overlords. They are were created by Khyber, one of the three progenitor dragons that created the planar system.
However, the dragons and the couatls - which were races created by the other two progenitor dragons - rose up to exterminate the Overlords from Eberron. Only a few Overlords are still alive, trapped across Eberron, and Ral Tulkhesh is one of them.
4 Tarrasque - CR 30
- Challenge Rating: 30
- Size: Gargantuan
- Type: Monstrosity
- Alignment: Unaligned
- Homeland: Prime Material Plane
- Found In: Monster Manual
The Tarrasque's name strikes fear in the heart of almost anyone on the Prime Material Plane. For a long time, it had the highest challenge rating of any monster in Dungeons and Dragons, and, even though more CR 30 monsters exist today, any party will still need to perfect their fighting skills in order to take it down. By some accounts, only one Tarrasque exists, and it could be permanently dealt with it someone found a way to lock it away on a different plane. However, not many have been foolish enough to try such a feat.
3 Aspect of Tiamat - CR 30
- Challenge Rating: 30
- Size: Gargantuan
- Type: Dragon
- Alignment: Lawful evil & Chaotic evil
- Homeland: The Nine Hells/Avernus
- Found In: Fizban's Treasury of Dragons
There are two dragon deities who are siblings - Tiamat and Bahamut - that are locked in an eternal rivalry. This foe is an aspect of the Evil deity, Tiamat. An aspect of Tiamat or Bahamut is essentially one of their followers who has died and been brought back to life, now bound to their master forever. Aspects differ from avatars because they are independent beings, whereas avatars are the god themself (or at least, controlled by the god themself) in another form.
2 Aspect of Bahamut - CR 30
- Challenge Rating: 30
- Size: Gargantuan
- Type: Dragon
- Alignment: Lawful Good
- Homeland: Celestia
- Found In: Fizban's Treasury of Dragons
Bahamut is the Good diety counterpart to Tiamat. While there's no official statblock for Bahamut himself, there is one for his aspect.
Bahamut sends aspects as emissaries, uses them as guardians, or for other critical tasks too important to be left to a mortal. Since Bahamut is the Good deity, you may worry about finding a reason to have your players fight this aspect. There's no reason to worry, though, because Bahamat is known for testing the strength of his followers and others whom he interacted with.
1 Tiamat - CR 30
- Challenge Rating: 30
- Size: Gargantuan
- Type: Dragon/Fiend
- Alignment: Lawful evil & Chaotic evil
- Homeland: The Nine Hells/Avernus
- Found In: Rise of Tiamat
If you really want to be true to the game's title, you could always put your players up against the literal mother of evil dragons herself. Tiamat has one head for each of the major species of chromatic dragons that we've listed above; they can all operate independently and use that dragon species' abilities. And if you want to throw a twist into the game, you can even use one of Tiamat's avatars to gain the players' trust before the big reveal. Her most common avatar was known as the Dark Lady: a human woman with long black hair.