Summary
The Underdark is one of the most daunting places to visit inDungeons & Dragons.It consists of a whole world beneath the surface, with its own fauna and flora, as well as sentient species with their own societies, religions, cultures, and civilizations. It’s also an extremely deadly place to go, with little guarantee of ever returning.
Whether you’re using an adventure that takes place there, such as Out of the Abyss, or you’re creating your own story that involves visiting these lands, there are quite a few ‘monsters’ that you can use as enemies or even neutral creatures or allies, depending on how the story unfolds.
It’s worth mentioning that D&D books consider most NPCs with prepared stat blocks to be ‘monsters,’ even characters like commoners, priests, and nobles. With that in mind, we are considering sentient creatures with their own societies as well as actual monsters.
11Drow
It Ain’t The Underdark Without The Drow
Drow can be powerful enemies at any level, are abundant in the Underdark, establishing whole cities there, and have fascinating lore concerning their culture. The children of Lolth are perfect candidates for bad guys, and you can run nuanced plots about their perspective of right and wrong within their society.
Followers of Eilistraee or ones that hate Lolth are perfect candidates for good Drows, too, or even use less common variations, such as the szarkai.
You can always re-skin humanoid monsters, like an Archmage, into a Drow and use them here.
10Drider
Spider-Drow
Whenever a drow fails attheir Goddess' test,they can turn into a drider, becoming monsters even in the eyes of the drow, and often suffering from madness, since the transformation is extremely painful.
They can be formidable foes due to the powerful resistance and strength they gain from this form, and they have a spellcaster variant, so they can be a threat both physically and magically.
9Duergar
There’s More To Life Than Elves
The duergar are to dwarves what the drow are to elves. Though they lack the religious fanaticism the drow have, they still have many prominent societies, and they’re known for being outstanding at crafting materials.
Sadly, they’re also known for their greed, violence, and the use of slave labor. Still, feel free to develop more nuanced duergar throughout your story, making things more complex.
We recommend adding the deep gnomes, also known as svirfneblin, among drow and duergar societies as the slaves - though drow can slave duergar and vice-versa. This topic is hard to avoid in an Underdark story, so you might as well lean into it. Freeing slaves can become part of the story, even.
8Kuo-Toa
The God Makers
Former slaves to the mind flayers, the kuo-toa live in secluded settlements in the Underdark, and though they’re sentient, their minds have been broken to the point that insanity has taken them. They’re also known for being religious.
In fact, they have the power to create Gods once enough kuo-toas begin to believe and worship the deity, so they can be used for interesting plots within the campaign.
7Neogi
Mind-Controlling Bug
If your players' levels are still low, the Neogi can be a formidable opponent - and a group of them can be challenging in the future, too. These small bugs have poor concepts of feelings, decent intelligence, and the power to control others.
Between multiple attacks and the ability to mind-control someone (a trait many Underdark creatures have), you can turn allies against one another while also having a creature that is not too hard to kill early on.
6Vampire Spawn And Vampire
For A Complex Story
Any undead is worth addingto the Underdark due to experiments, dark magic, and whatnot. That said, the Underdark is a perfect place for a vampire, as it is a massive land with no sun.
Not only are vampires strong opponents, but you can get strong story material here. Perhaps a vampire spawn who escaped their master and is hiding in the Underdark, to an actual vampire creating a new home along with the civilizations beneath the surface. A drow vampire would work beautifully here.
5Mind Flayer
Eat Some Brains
After their big intergalactic empires failed, mind flayers became smaller colonies that can be found hidden in places just like the Underdark. A whole group of them, controlled in a hive mind by an elder brain or an independent one controlling another species, are perfect candidates for a side-quest area or a specific dungeon in your story.
They’re known for their powers to stun and mind control others, as well as surprisingly strong tentacles they wrap around their victims to eat their brains.
4Aboleth
The Fake Gods
The aboleth are another group of mind-controlling creatures who lost their former empire, and can now be found in lakes throughout the Underdark. And truth to be told, their mind-control abilities are as efficient (if not more) than that of the mind flayer.
They’re terrifying, intelligent, and the perfect choice for enemies to use whenever you have an underwater section in your game and want to add some combat to it.
3Beholder
Where Beauty Lies
One of the most iconic monsters in D&D, beholders can often be found in the Underdark. They’re known for being intelligent and quite xenophobic, killing other creatures for pleasure or enslaving them as a show of power.
In battle, they’re notorious for their Antimagic Cone and their rays with random effects that can go from putting someone to sleep to turning their body into dust.
2Purple Worm
Just A Good Ol’Monster
We’ve focused too much on intelligent creatures, so how about an actual monster? Purple Worms are perfect for a more unorthodox fight, as they are gargantuan in size and can fight while being underground, coming out only to attack.
They’re tough, extremely strong, and don’t require vision to see their enemies, making it quite difficult to hide from them. Between their strength and poison, a single strike could cause damage of an average of 61 hit points.
