The key to any great Dungeons and Dragons campaign is the story, and the best part of said story is the conflict. After all, this is likely the reason behind the party's adventure. The culmination of all their hard work and labor, and the best way to end the climax of a D&D adventure, is with a thrilling boss battle. Not just any boss monster, either, but a monster that has been behind the scenes the entire time.
Now, despite the game's name, dragons aren't the only monsters to pick from when choosing a big bad. There is a whole slew of monsters with unique and terrifying abilities that make them far more interesting than a simple dragon. While the giant lizards are iconic, there are many monsters far more deserving of the title of "big bad".
Updated March 5, 2023, by Dexter Adams: When it comes to the 'big bad' of a campaign, most scour the Monster Manuel for the strongest and deadliest monsters. They want their game's final enemy to be as strong as possible, however, this doesn't have to be the case. Sometimes, the best end-game villains are the ones with a plan. The monsters whose lore can add depth to a campaign rather than the monster with the higher CR rating.
14 Death Slaad
As beings of chaos, the goal of the slaadi is to cause chaos. They traverse the planes, taking pleasure in the pain and suffering that their incursions inflict upon the realms. Normally, these creatures are disorganized and can be handled with a good enough plan, but what would happen if this weren't the case? What if these creatures had a leader to keep them on track?
Death slaad are 'blessed' by the Negative Energy Plane. This not only makes them stronger but also smarter. Smart enough to lead entire armies of their brethren into the other planes. Having a group combat these incursions would not only allow you to use an underrated monster but also grants your players the chance to explore Limbo as they search out the slaadi leader.
13 Solar
Upon seeing an angel, most wouldn't assume them to have evil intentions, and they would be right. In D&D, angels and other celestial beings are explicitly classified as Good. For a celestial being to be Evil, they would have to Fall, thus becoming either a demon or devil. That said, Good is relative.
An act of good could very well be seen as evil to someone else. If a solar happened to have the belief that the realms had become corrupted, it would be in their nature to eradicate this corruption by any means. They would send a legion of other celestials in hopes to eradicate this corruption, even if that meant destroying the realm. This would be the perfect adversary because, in their eyes, they are still just, but to everyone else, they're evil.
12 Mummy Lord
Stephen Sommar's The Mummy breathed new life into the titular movie monster. What was once a zombie wrapped in dirty bandages had become a borderline godly being. Imhotep was able to raise an army of the undead, manipulate the elements, and drain the life force from the living. Had he not been stopped, Imhotep would have taken over the world with his power and D&D's mummy lord shares these traits.
Much like Imhotep, a mummy lord is capable of numerous feats of magic granted to them by the dark gods. They're often seen protecting ancient temples, but these monsters maintain their memories and personalities from their previous lives. It wouldn't be outrageous for a mummified tyrant to return with an undead army, seeking to continue their desire for conquest.
11 Atropal
Atropals are mistakes. They are the abandoned projects of evil gods, cursed to drift in limbo, neither alive nor dead. Most of these creatures were sealed and abandoned by the gods in crypts or empty planes of existence. Because of this, atropals hold a deep resentment for everything and everyone.
If one of these monsters were to be freed, especially after centuries of being left to wallow and despair, revenge would be the first thing on their mind. After years of planning, rather than simply attacking mindlessly an atropal could easily lead an incursion across the Material Plane. With its godly origins and connection to the Negative Plane, an atropal could very well be a world-ending threat.
10 Kraken
When most think of a kraken, they imagine a titanic monster with dozens of tentacles and a penchant for destruction. In D&D, however, there is a level of depth to these creatures that most don't know. At the beginning of time, krakens were warriors of the gods. When these creatures freed themselves, their goal became the destruction of everything their masters had created.
Aside from being a kajiu sized monster, krakens are incredibly intelligent. They're cunning, preferring manipulation to outright destruction. With their cults, their influence extends to the land, giving them a firm hold in nearly every corner of the Material Plane. With this type of influence, it would be child's play for an ancient being like a kraken to destabilize a kingdom or two, leaving them weak and unable to defend against a kraken's power.
9 Lamia
A lamia, while weak, does make decent big bads for a low-level adventure or even a one-shot. These hedonistic creatures make for a perfect tyrant for a town or a city — they enslave everyone they can, weakening their minds to make them subservient while hoarding their treasure. Additionally, it's noted that these creatures take special pleasure in corrupting pure-hearted adventurers.
It could be a party was summoned to retrieve townspeople that a lamia stole and enslaved, or it could be that the lamia itself brought the party there if only to watch the group break under their power. If a party can escape a lamia's illusions, they still have to face off with the mind-controlled servants, all of whom would gladly give up their lives for their master.
8 Vampire
How many vampire movies have there been now? Vampires are and always will be great villains. They're tens of times stronger and faster than any human, capable of hypnotizing any who dare meet their gaze, and they're incredibly difficult to kill. You may think they're overused or overhyped, but there's a good reason why they are so common.
Even in D&D, vampires reign supreme as one of the game's deadliest encounters. These creatures could be tyrants brutally conquering and feeding off of anyone who stands in their way, much like in the Castlevania series, or they could be the puppet master behind the scenes, manipulating people in power to get their way. Either way, vampires make for very tricky and deadly enemies.
7 Death Knight
Most look at the death knight as a skeleton with paladin levels, but these undead monsters are so much more than that. For one thing, death knights are created when a paladin falls from grace without atoning for their sins. They maintain their ability to cast non-healing divine spells, have control over lesser undead creatures, and can't be killed until they atone.
While these things alone don't necessarily make a death knight worthy of being the big bad of your next campaign, take into account its decent Intelligence score and high Wisdom and Charisma. It wouldn't be out of the question that a tyrannical death knight sends out their undying army to conquer a kingdom. Much like the White Walkers from Game of Thrones, sometimes the best enemy is one who just wants to destroy.
6 Rakshasa
Not every big bad needs to be an incredibly powerful or over-the-top force of nature. Sometimes, the best enemies are the ones with a more delicate approach. Rakshasas, despite being fiends, truly thrive in misdirection and manipulation. They often take the appearance of someone in power, using both wealth and status to hide in plain sight and plain its machinations.
What's more, as rakshasas will reform the only way to truly kill this creature is to travel to the Nine Hells. Once reformed, rakshasas will hunt down the ones that killed it, and they won't just confront their killers. No, these creatures will kill anyone and everyone close to their killers to draw them out. Families, friends, and whole nations could be destroyed before these creatures are satisfied.
5 Beholder
Visually, beholders are one of the scariest creatures in the Monster Manual. In terms of stats, beholders are definitely one of the scariest creatures in the Monster Manual. With an array of eye beams that can instill fear or outright kill a creature, beholders are terrifying encounters for a party of any level. These aberrations are more than just a random encounter.
Beholders are incredibly paranoid creatures. They mostly live in isolation due to this, but the reverse is possible. Much like Xanathar, it wouldn't be abnormal for a beholder to reside in a city, using its powers to keep everyone under its watchful eye. A beholder's paranoia could even have it lead an invasion across a continent in an attempt to destroy those jealous of its power.
4 Lich
Power corrupts and absolute power corrupts absolutely. This is the fate of any wizard seeking powers beyond their comprehension. Whether it be due to their thirst for immortality and power, or they are tempted by a powerful evil entity, wizards that embrace undeath become skeletal spellasters known as liches.
A campaign could be centered around stopping a lich in its never-ending quest to consume souls, or it could even be about stopping a wizard from becoming a lich. There are countless options on how to run a lich, and the story doesn't have to end with its death. The campaign could easily continue with the party seeking out the lich's phylactery so that it doesn't return.
3 Lolth
For a group of adventurers reaching the tail end of a long campaign, nothing is as satisfying as showcasing their strengths against a powerful foe — and what better foe than a god? These beings are the pinnacle of D&D. As the strongest to exist within the world, what better way to showcase a group's strength than to go up against something like that?
There are many evil gods in D&D that would make for a riveting battle, such as Vecna or Tiamat, but Lolth outclasses them for several reasons. For one thing, she has a concrete motive in why she would attempt a worldwide catastrophe in her desire to be worshiped by all. She also has heavy ties within Drow culture and influences in the Underdark, giving another plane of battle should players choose to face her.
2 Elder Brain
Mind flayers have surged in popularity in recent years. This is possibly due to the creature's inclusion within the ever-popular Netflix series Stranger Things. However, unlike how it was portrayed in the show, mind flayers aren't the 'boss' of the hive. That role goes to the elder brains.
These oversized hunks of gray matter are the literal brains behind the illithid's operation, and master manipulators in general. Elder brains are capable of controlling one's senses, mind, or simply turning someone's brain into mush. Having such a creature controlling the people in power from a distance is not out of an elder brain's wheelhouse, and would lead to a mind-bending mystery and battle when this is discovered.
1 One Of The Demon Lords
Juiblex. Rakdos. Graz'zt. Orcus. Demogorgon. These are just a few of the terrifying demons to be called 'lords' in D&D. These monsters are the best of the best, or the worst of the worst depending on who you ask. While their titles were self-appointed, they are definitely well deserved given how terrifyingly powerful each one is.
What's even better, if you do choose to use a demon lord as the end boss, is that you can use the others for your benefit. The demon lords, by nature, despise one another. They consistently scheme war against one another in the hope of expanding their respective realms within the Abyss. If a party is hoping to defeat such a demon, it would be likely that another would offer their aid. For a price.