Dragon Encounters

Making dnd combat fun, finding monsters that fit together, monster tactics and strategies, and other ways of using the monsters of dungeons and dragons

BALOR: Using a Volcanic Eruption in DnD


I just want to remind people that I avoid matching monsters with other monsters of the same type [for example: demons with other demons] because I want to help people come up with ideas they might not have come up with themselves. It is not because I somehow missed the completely obvious.

Combat rating 21


1 Balor (CR 19)

4-5 Fire elementals (CR 19)


Combat rating 22


1 Balor (CR 19)

2 Nycaloths (CR 19)

1 Ultroloth (CR 19)


Combat rating 24


1 Balor (CR 19)

2 Efreet (CR 19)

2 Remorhazes (CR 19)


Combat rating 26


1 Balor (CR 19)

1 Ancient red dragon (CR 19)

How to use – Demons

The monster manual has quite a large number of demons. One thing I noticed, however, is that there doesn’t seem to be much connection between the different demons. If you gave a player who is unfamiliar with D&D a set of pictures from any other set of related monsters, mixed up with a few random unrelated monsters, they should be able to sort out the categories fairly easily. If you were to try it with demons, I doubt they’d have a chance. Even devils have more shared characteristics than demons.

As an attempt to deal with this, I want to suggest a few possible ways to adapt the demons very slightly in order to give them some shared characteristics. The first two ideas are descriptive, the second two affect the demons’ behavior. None of them change the demons’ fighting abilities, and as such they shouldn’t classify as homebrew. [Although I will provide a way to turn the second idea into homebrew also, if you want such an effect.]

The ideas are ranked according to how much of a difference they should make in your game, from least to most.

  1. Every demon is always happy to see PCs [I.E., potential victims] approach. If they don’t need to hide this for some reason they will generally grin, showing sharp teeth, and salivate. It doesn’t matter how badly the odds are against the demons’ winning. Just the possibility of violence excites them.
  2. Any person catching sight of a demon’s eye will see in it a raging hate, a desire not just to kill but to utterly destroy. They would grind the very atoms of their targets’ essence out of reality if they could. *
  3. No demon will ever flee. Ever. In addition to the bloodlust which drives them on beyond reason, they also know that if it becomes known that they fled, they will be branded as weak, whereupon they will be a permanent target of every other demon for the rest of their existence. [Weakness is the cardinal sin of the Abyss.] This rule applies even inside the Abyss.
  4. Demons will attack unconscious PCs. They don’t only want to win a fight; they want to utterly destroy their enemies. Any enemy within reach who is unconscious but not dead will be targeted by one of the demon’s attacks, even if that’s a bad idea tactically. [With the balor, we’ll consider the automatic damage that comes from standing near it as one of its attacks, given that it’s a CR 19 creature with only two attacks a round.] (I was originally planning to suggest that even after taking down a PC they will still focus all their attacks on him until he’s dead, but because so many demons have three or more attacks a round, which means they would kill the unconscious PC in one round, I toned it down a bit.)

* This doesn’t have to have an effect on the battle, but if you want one, I would suggest as follows.

Any PC looking a demon in the eye is affected by a spasm of fear. They have to make a WIS save equal to 10 plus half the demon’s CR [rounded down], or suffer the following effect for one turn.

A jolt of fear goes through the PC at the sight, and for a second everything else in the battlefield seems almost unreal. He loses ten feet worth of movement from disorientation, and his AC and saving throws are reduced by two for one round due to fear.

A demon can only affect one player a round with this effect. Once a player is forced to make this save, he is immune to this effect for the rest of the day. The immunity is good against all demons, except ones with a higher CR than the one whose eyes he met.

Combat Encounter: (difficulty 20)

Stage 1. The Balor’s Restraints

(This combat encounter is presented as three stages that run into each other.)

The villains are seeking to wreak wide-spread destruction for whatever reason. To do so, they have summoned a balor within or above a volcano, and the balor will explode it onto the region if given the time. Or perhaps they’ve summoned it for another reason, and thanks to the players interference it is threatening to escape.

When the players manage to reach the peak room [the boss battle room] the ceremony has just been completed. A balor stands within the pentagram, his fire filling the inside of said pentagram. At each of the five points of the pentagram is a large candle. One of the candles is out, and another will go out every round at initiative 20. When all the candles are out or destroyed, the balor immediately escapes. (This means that the balor will escape toward the beginning of round 4.)

If any area-of-effect spells hit one of the candles, they may destroy it and quicken the balor’s escape further. Assume a modifier of +0 for each of the candles, and if it fails a save it is put out or destroyed. (This is regardless of how much damage the spell does, so long as it does any. They also don’t get put out if they make the save, despite the fact that creatures making the save still suffer half-damage.)

The balor can’t leave the pentagram until all the candles are out, but his attacks can. Given the vast range of his attacks, you can make the room be as large as sixty feet, so long as the balor’s pentagram is in the middle. (The most thematic place for it to be, anyway.)

The balor’s strategy is obviously to use its whip to drag PCs toward it, and then hit them with its sword. I already described its pentagram as filled with flame, and I would just describe the fire damage from being near a balor as coming from this flame. (In the future stages, after the volcano erupts, the balor will have drawn some of its heat into itself and be glowing with that heat. Coincidently, that heat will do the same amount of fire damage as the flames in this section do. Since you’re rolling the damage dice, the players may or may not realize that the damage is the same.)

Once all the candles are out, move on to the next stage.

[When running a multi-stage fight, there is always a chance that the players will finish off the monster before you’re ready to continue on to the next stage. Mythic actions gave one way to deal with this, but that won’t work in this case, given that I’ve given an external timer. You might want to give a fight or two on the way to the balor’s chamber to help use up spell slots in advance (depending heavily on the players’ levels,) and I’m hopeful that the short time frame and the added challenge of having to avoid hitting the candles will prevent the players from winning too fast, but if they do kill the balor before the timer runs out here are three ways to deal with it:

  • An alternative boss fight. Have the summoners show up and try to kill the PCs in revenge for wrecking the summoning.
  • Continue on with the scenario anyway. Have the volcano erupt, and have the players face the dangers you had in mind, and tell the players that the volcano is erupting more slowly and over a similar area than would have been the case if they had lost the last fight. In essence, give them the impression that losing that fight would have been instant death, and that you intended them to win it in order to continue the scenario. (Note: Lying to your players like this only works if you never let it slip that you lied to them. Even after the game, even after the scenario ends. So long as you plan to DM for them again. I would add that I don’t feel lying in this case is morally wrong, since what they want is an exciting game and this helps give it to them, but you don’t have to choose this option if it bothers you.)
  • Announce their victory then and there. It was probably a reasonably good fight, and even if it wasn’t as epic as you imagined, sometimes life works out that way. (If you want, you can blame me for making a scenario that was too easy. Whatever makes you happy.)

Note that if you continue the scenario anyway [the second option] you’ll need alternative monsters for part 3. I would suggest a marilith, or a set of three efretee [possibly rebranded as demons,] at least one of which has a Rope of Restraint. If you choose one of the other options, you can always use a volcano again later in the campaign and that time start from part 2. [That time they arrive a bit later.] There are any number of video games where the players first have to avert something from happening, [with it being instant game over if they lose,] and then later on having it automatically happen and them having to deal with it.

Stage 2: The Eruption Begins

As soon as the last candle goes, the ground starts shaking and all the PCs are automatically knocked prone. Regardless of turn order, the balor spreads its wings and takes off through the ceiling, shattering it behind him.

The heat begins to increase, and fiery cracks begin to appear in the floor. The volcano is going to erupt in the very location where the PCs are located, and they have to escape while they still can.

[If they have any teleportation magic, you’ll have to find a way to stop them from using it. You can establish that there is a spell preventing teleportation into or out of this area. (As such elements work better when set up before they’re needed, they feel less like convenient cheating that way, you might consider establishing this fact before they enter the location in the first place.) You can make their goal to destroy the anti-teleportation spell in order to escape instead of trying to get out of range of the volcano as I present it below.

A different way to deal with teleportation magic is if they have a goal that requires them not to flee. Perhaps there is a powerful magic item that they need to gain before the volcano destroys it. They can teleport away, but then the item will be lost. If you use this approach, you might want to place the final fight against the balor right where the item is, and you can have lava surround the location and be threatening to engulf it. They’ll need to hurry if they want to escape in time.]

I would suggest using a battlemap. There will not be a foe, as the balor is gone and any other foes have fled, but there will be several fiery trenches lying around that they have to get past. [Think of these trenches as open pit traps with Walls of Fire rising out of them.]

The shaking of the ground can either be used to give them disadvantage on all physical skill checks and to force them to make a save against being knocked prone every so often, or you can have them all narrate what they’re going to do, then add a sudden tremble to the ground in the middle of some of the rounds everybody who fails their save will find their turn messed up. Even if you choose the first option, don’t forget to narrate the constant shaking of the ground and the sudden increase at the point where you force them to make DEX saves.

Loose boulders and collapsing walls are also going to be a challenge. I would probably give the players knowledge of where the boulders are going to go and where there’s going to be a collapse at the beginning of the round, and then they can add avoiding these areas to the items they’ll have to deal with each round.

Tasha’s suggested that the effects of the fireball spell be used to mimic explosive fireballs sent up from the volcano. While not an interesting feature in itself, it can help contribute to the urgency of escaping. It will also wreak havoc on all spells requiring concentration.

If there are any humanoids left, they’ll be trying to escape also. They might even help the players escape, if dealing with an obstacle proves mutually beneficial, but they might also push a PC out of the way and into a fire trench if it will let them escape.

After they escape the immediate area, there will still be various volcano related obstacles that they’ll have to deal with. I would suggest using 2-3 of the following:

  • A section of the mountainside collapses right next to the players. The players have a single round to figure out what to do. Afterwards, they might need to dig out those PCs who got buried. If you want to make matters more urgent, lava is flowing out of the collapsed area and moving toward them. Better dig out those PCs quickly.
  • A wide trench of lava has opened up in front of them. Unlike the trenches above, this one is too wide to jump through. You can give them a narrow ledge to travel along, or stepping stones for them, but be aware that these areas will be red hot [as will the air above the lava.]
  • Steam vents are opening up and causing the area ahead to have poor visibility, as well as being deadly traps themselves. (You’ll want to have carefully mapped the area, with its various higher and lower lands, as well as any loose rocks, boulders, or any such like.)
  • A valley lies ahead, filled with poisonous gases. Perhaps they can climb along the edges.
  • The gases push out a heap of rubble, and send it rushing ahead toward the PCs. They can’t outrun it. They’ll have to climb the walls of the chasm they’re in, and do so fast, so that they can get out of the way.
  • A previous eruption of the volcano left behind an open lake, which is now boiling hot. Alternatively, the walls of the lake were just destroyed, sending a wall of [possibly boiling] water rushing at the players. Or, crack opened up underneath the lake, and now the water is being pulled down in a whirlpool. [Note that the first two options are somewhat similar to other ideas above. You probably don’t want to use this together with those ideas.]

While they make their way out of the area, you’ll want to throw in descriptions of the ground shaking smoke rising. Perhaps pull some descriptive elements from ideas that you’re not using.

Stage 3: The Volcano Erupts.

Narrate them walking for several exhausting hours, until they’re forced to take a short rest to regain energy. (And, more importantly, to regain HP in preparation of the upcoming boss battle.) At the end of their short rest, the volcano erupts.

Unfortunately, I have yet to meet a party with the patience to sit through a long description. You’ll want a quick description that you can narrate in a few tense sentences. Perhaps a quick description of how the fountain of fire lights up the sky, blasting boulders high before it and sending down clouds of ash or burning embers all around for miles.

Fortunately for the players, the area that they were trying to reach, whether it’s an escape from the area or an item that they need to obtain, is closer than they realized. Less fortunately, the balor is waiting there to meet them.

The balor should probably be assumed to have taken a short rest while they were dealing with the obstacles of part 2. (I doubt the balor has enough HP left after part 1 for a good battle otherwise.) Below are a few different scenarios for the final battle for you to choose from:

  • Burning embers have set the vegetation ablaze. They will be fighting the balor in the middle of a fire, which will be doing a certain amount of damage to each of them a turn. Escaping the fire is impossible, as the balor will just use its whip to pull them back in.
  • The ashes from the volcano are rendering the area heavily obscured. They are probably also reducing movement due to their thickness.
  • Lava is flowing toward the area, and they have to defeat the balor fast if they want to escape out of the way.

Optional ending: When the balor is reduced to forty or so HP he grapples a PC and announces that if he is killed, not only will he be sent back to the Abyss but the PC he’s holding on to will be taken there with him. He is not willing to negotiate (demon, remember) but his threat might well cause consternation among the players. Perhaps they will even try to find a way to free the PC before destroying the balor. If they ignore the threat, at least it will ensure that one PC is in range of the final, destructive explosion.

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About Me

I have been a DM for several years, and I was designing home RPG games since my young childhood. I have been a fan of many different types of games (computer, board, RPG, and more) and have designed several for my own entertainment. This is my first attempt to produce game content for a wider audience.