Because of the contradictory lore between different editions and campaign settings, it’s difficult to definitively state the most powerful beings in Dungeons and Dragons canon.
Ultimately, the DM decides which beings have the most power in their in-game universe. This means who and what is considered the most powerful can change from table to table and from campaign to campaign.
That said, there’s a ton of preexisting lore that can help narrow down the options. If you’re looking for some ideas for a big bad to use in your game, here’s a list of some of the most powerful beings in existing D&D canon.
10. The Primordials
It took the combined strength of all existing deities, both good and evil, to combat the powers of the Primordials. In the end, the overgod Ao had to rip the world into two, dividing it between the two groups to prevent further conflict.
Current lore of the Primordials is a little nebulous and they haven't been a huge influence since the 4th edition of D&D. Hoping to return the multiverse to a state of elemental chaos, they could be an interesting ancient power to introduce into your campaign.
9. The Great Old Ones
The gods, while divine, are largely understandable. They have emotions, petty squabbles, jealousies, and other relatable motivations. This isn’t so with the Great Old Ones.
Heavily inspired by the works of HP Lovecraft, Great Old Ones are ancient, alien beings beyond mortal comprehension. Just the sight of one can drive a person to madness, so incomprehensible are their physical forms.
8. Vecna
His ultimate goal is to destroy all the other deities and rule over the multiverse. He came perilously close to accomplishing this when he tried to take over Sigil, the city at the center of the multiverse. From there, he would have had the power to rearrange all of existence
While no longer an imminent danger, the possible reemergence of the lich god would be a considerable threat to the entirety of existence and an interesting obstacle to introduce in your next campaign.
7. The Serpent
Considered one of the most powerful entities that have ever existed, there are a few different theories on the nature of the Serpent.
Some say it’s simply an alias for a mysterious being known as Mok’slyk, one of the Ancient Brethren that predate the gods. Another is that the Serpent's true identity is actually Asmodeus, another being on this list, whose true form is that of a gargantuan serpent. Some believe the Serpent to be a personification of pure magical power.
6. Asmodeus
Asmodeus is more ancient than even the concept of faith, and because of this does not rely on worshippers for his power as other gods do. He is considered by some to be one of the ancient brethren who have existed since the beginning of the multiverse.
5. Tharizdun
A primordial deity ruling over eternal darkness, madness, and entropy, Tharizdun poses a threat to the entire multiverse. He is responsible for the creation of the Abyss during the Dawn War, which caused the rest of the gods to unite against him. Too powerful to be destroyed entirely, both good and evil deities had to unite in order to imprison him and prevent the destruction of existence itself.
Still, vestiges of his power can sometimes leak into other planes and influence other beings. Tharizdun is one of the only entities that could have potentially ended all of existence, and if he was ever to escape his imprisonment he would once again pursue his goal of eradicating all that exists.
4. The Lady of Pain
A supremely powerful entity, the Lady has authority over the literal center of the multiverse and can open and close the portals within the city at will. She is capable of preventing the gods from entering her domain and unlike them, does not require worshippers to maintain her power. In fact, she resents being prayed to and often kills those who attempt to do so.
The Lady operates more as a symbol or force of nature than as a deity, and it’s suggested that revealing her true form would cause the universe itself to unravel.
3. Ao
As a god among gods, he has authority over all other deities within his sphere of influence. As such, he can demote, permanently damage, or even kill the other gods and can bestow divinity upon mortals. He does not require the worship of mortals to sustain his power and is one of the supreme powers in D&D canon.
2. The Player Characters
There’s always the potential that over the course of a campaign the PC’s will acquire enough power to overthrow even the gods and by 20th level, there’s almost nothing that can stand in their way.
But more than that, the PC’s are powerful in that the entire world exists for their benefit. The universe shapes itself around their choices, actions, and desires. An unnamed NPC can become a hugely influential part of a campaign, simply because the PC’s took an interest in them. What the players find interesting and pursue or find boring and discard shape the entire narrative of the campaign, and that is what makes them so powerful.
1. DM
The DM has ultimate control over the ingame world. They create the scenarios the players encounter, voice every NPC and enemy, and react to player actions on the fly. Even with prewritten campaigns, the DM is the one who ultimately decides what to discard, keep, and adapt.
While the players shape the world with their choices, the DM is the one who decides the consequences of those choices and how they will impact the narrative. Even the other entities on this list are really under the DM’s command and will triumph or perish as they please.