Summary
When playingDungeons & Dragons,there are many beautiful places across its many settings and worlds that you’re able to take your players to. The Abyss is not one of those places, thanks to its extreme connection with the essence of evil itself and all the demons lying around. It’s perfect for an action-packed adventure, though.
The good thing about a campaign centered around demons or that involves going to the Abyss is that there are many demons to choose from. The bad thing is that there are so many, and you may be unsure which ones to use. Thus, we’re here to help you filter things out.

The bosses of yesterday could be the minions of tomorrow. If your party’s level is so low that a CR five creature can be a challenge, you can stick to having only one of them in the fight. As they progress and level up, you can use a small group of these creatures to show your players how much stronger they’ve become.
10Cackler
For Fighting And Roleplaying
Despite the lack of multiattack, a Cackler can use Fire Bolt and Tasha’s Hideous Laughter (the latter only once a day), giving them a few fun options during the battle. They can also imitate voices they have heard before, making them fun creatures for tricking the party. You can use the voices of friendly NPCs asking for help as a way to lure the players into a trap.
Cacklers won’t be very effective by themselves, but they can support other monsters with their tricks. Plus, they explode when they die, which is a fun ‘gotcha’ moment for the players without being too much.

9Rutterkin
Scarier As A Group
Some demons have fun tricks as a group, and Rutterkin is one of those demons. They get to immobilize enemies, causing both the frightened and the restrained effect at once, making them powerful opponents.
And the players will have a harder time escaping these conditions if six Rutterkins or more are nearby (don’t do this to low-level groups, though). Its bite can also poison, and if Rutterkin zeroes someone’s health while they are poisoned, they’ll die instantly and become demons themselves.

8Tlacatecolo
An Exhausting Fight
For starters, Tlacatecolo has Magic Resistance and multiattack, and it can also disguise itself as a regular owl for a nice surprise attack against the party (though if they are in the Abyss, they’ll probably be suspicious of the random owl).
The fun trick here is the recharge ability, which causes damage, stops them from recovering hit points, and can causelevels of exhaustionuntil it gets properly healed. If you’re using one of these outside the Abyss, they tend to use particularly dark places as their nests.

7Echo Of Demogorgon
‘Mind Control’ Without Being Too Annoying
The Echo of Demogorgon is a fun minion to have if you plan to use the Demogorgon later, and they’re quite strong, too. They get two attacks and Magic Resistance and can use their bonus action to force a Wisdom saving throw, and upon failure, you can choose between causing damage or forcing the target into attacking someone else.
Forcing players to sit back while their characters are being controlled can be annoying, so just forcing a single attack is a cool way to diminish that. Plus, you may use that every round since it’s just a bonus action.

6Maurezhi
Maurezhi is another example of an enemy that isn’t particularly strong in itself but will benefit from a good enemy composition. It also has Magic Resistance, along with the ability to change its appearance to someone it consumes for a few days while also taking their memories, allowing them to imitate their victims with precision.
Its bites can decrease the player’s Charisma, potentially killing them quickly and turning them into a ghoul within 24 hours. Its claws have a chance of paralyzing, and it hasa recharge abilitythat allows it to raise Ghouls or Ghasts to their full health, meaning that having these creatures (or just a bunch of bodies) around can make the fight more challenging.

5Glabrezu
Grapple, Punch, And Cast
Glabrezu has two pincers and two hands and can use them all at once, giving it a multi attack of four strikes. If they hit someone with the pincers, they automatically grapple the target and can hold two creatures at once (all that only counts if they’re medium or smaller). They also have spells at their disposal, so you have alternative fighting styles here.
They are known for corrupting people, searching for those who are interested in becoming more powerful and tempting them with it, possibly turning people into demons in the process. If a PC is turning to the dark side, Glabrezu is your guy.

4Master Of Cruelties
Make Them Attack Each Other
The fun of Master of Cruelties is to have the group attack one another. Along with spells such as Dominate Person, the Master can charm creatures with spells and recharge abilities so they can’t be the target of an attack.
Because of their charms and the powerful aura around them, they can force people to attack while preventing them from being targets, forcing players to hit one another instead. They don’t have much lore themselves, but judging by their mechanics, a sadistic personality fits them, as you just laugh it off while forcing your enemies into hitting one another.

3Crokek’toeck
Pronunciation Not Included Here
Crokek’toeck is our first specific demon entry rather than a breed of demons, and ‘Croke’ is also a one-demon-army. Narrative-wise, he can go to the river Styx unaffected, and he’s known for helping other demons traverse the river. It can’t do much. He’s not that powerful himself, but he has a cool trick to pull off.
Crokek’toeck has many other demons inside of it, and it can disgorge several creatures with this ability, among Barlguras, Gnolls, Dretches, Vrocks, and more. In other words, you may spawn several minions out of nowhere.

2Sibriex
Disgusting And Powerful
Sibriex can hurt nearby people at the beginning of their turns, cast spells like Hold Monster at will, multiple attacks, and even cause exhaustion to their enemies. They can be horrifying to even the strongest of characters, with a twisted design that will have you question how they’re even alive.
To make things more challenging, Sibriex also has Legendary Resistance and Legendary Actions. It can easily serve as a boss, even at higher levels. It’s safe to say Sibriex is one of the most powerful demons you have available.

1Demon Lords
We Recommend Orcus
If your idea is to have a campaign around demons, a Demon Lord is the best option for the final boss. There are many options to choose from, each being extremely deadly and with a backstory and place in the lore to help you with the campaign’s plot. You can grab somegreat options here.
That said, our ultimate recommendation would be Orcus. Not only is the character great, but its power is beyond most creatures, and even its minions are terrifying creatures (not many can use liches as minions, after all).