The ultimate DnD Cloudkill 5e guide and 6 ways you should use it

While this spell won’t win any awards for creativity any time soon, the spell mechanics of Cloudkill 5e are a lot more complex than the name would let you believe at first glance.

There are tons of questions about how it works, what classes are best to optimize it, and what exactly it does. I see both beginners and veterans ask these questions, so I think it is more than worth writing an in-depth cloudkill 5e guide about this conjuration spell. 

In this guide, I will tell you all there is to know about this powerful spell. I mainly write from the perspective of a Dungeon Master because that is how I most often play Dungeons and Dragons. However, I do think this gives me a lot of insight into what makes DnD fun for a player and how PC can throw a serious wrench in the plans of any DM who isn’t careful and did not think of making a blackout plan.

What is Cloudkill in 5e D&D

If you want to get a feel for what Cloudkill in 5e is, then you will need to use a bit of your imagination. Imagine you enter the lair of the final boss of the campaign, in this case, an elder lich who has been pulling the strings.

He sits on his throne, and you hear him whisper the words Cloudkill while making some hand gestures. But, of course, some of you will already know what happens next.

Fog spreading and effect

When the spell is cast, a 20 feet large sphere of poisonous fog that shines yellow and green is created. Then, the spell starts to form wherever the caster has pointed, for as long as it is within 120 feet. 

This fog does not remain 20 feet in radius but starts to spread. The fog keeps spreading until the spell’s duration has ended or when a strong wind – nature or magic – disperses the fog, which also stops the spell. The fog does not only create a poison gas, but it also obscures the range of sight for all those unlucky enough to be caught in it. 

Saving throw and damage

When a creature is within the radius of the smog, it needs to make a constitution saving throw. If it fails the save, the creature will take 20 or 5d8 poison damage. If it manages to be successful with the throw, then it only takes half this damage. Cloudkill will also damage a creature when it tries to hold its breath or does some kind of bag over its head. So getting damaged is as good as unavoidable. 

Movement and avoidance

The spell starts to work immediately so that Cloudkill will do damage the turn it is cast when there is a creature within the radius. The fog does not stay stationary, but it moves 10 feet away from you.

It is a bit heavier than normal air, so it does not go up. On the contrary, it starts to sink into the holes in the ground. This means you could avoid getting hit by the spell when you fly above the cloud. 

Scaling Damage with Spell Slot Level

Cloudkill 5e scales with the level of the spell slot you put it in. When you put the spell into the 6th spell slot, you can add 1d8 damage; if you put it in the 7th, you can add 2d8 damage; in the 8th spell slot, it will cause 3d8 more damage, and so on. That means at the 10th level, if you put it in that spell slot, it will be twice as strong and hit for 40 damage a turn on average when a creature fails a throwing save.

Spell AppearanceA 20-foot sphere of poisonous fog that shines yellow and green is created when the spell is cast. The fog forms where the caster has pointed within a range of 120 feet.
Fog SpreadThe fog spreads continuously until the spell’s duration ends or it is dispersed by a strong wind. It obscures vision within its radius.
Saving ThrowCreatures within the fog’s radius must make a Constitution saving throw. Failure results in 20 or 5d8 poison damage, while success halves the damage.
Holding BreathEven attempting to hold one’s breath or cover the face does not prevent damage from Cloudkill.
MovementThe fog moves 10 feet away from the caster, sinking into ground holes instead of rising. Flying above the fog can avoid being affected by the spell.
Scaling DamageCloudkill’s damage scales with the spell slot level. Increasing the slot level adds additional d8 damage (e.g., 6th slot adds 1d8, 7th slot adds 2d8, etc.).
Enhanced StrengthPlacing Cloudkill in a 10th-level spell slot doubles its strength, averaging 40 damage per turn against creatures that fail their saving throw.

What are the requirements to cast this spell?


Cloudkill is a level 5 skill. So you won’t have it when you start your adventure, but you will likely have it at the midgame of your campaign if you play as one of the classes that can use it.

That does not mean you won’t be able to use it in the end game. It has the advantage of scaling with your level if you put it into a higher spell slot. Every spell slot above the 5th one will add a 1d8 damage to it. In other words, the spell is twice as strong if you put it into the 10th spell slot. 

Casting time

The casting time of the spell is one action. Therefore, you will not be able to use any extra attack if that also takes a normal action. However, you will still have access to your bonus- and movement action after casting this spell. Remember, you only have one normal action per turn. 


Spells in Dungeons and Dragons generally have multiple components. Cloudkill is no different. In this case, there are two, a verbal component and a Somatic component. 

Verbal: This means the words need to be spoken; you have to say the name of the spell to cast it. In other words (no pun intended), you must be able to speak. Your mouth can not be restricted by a spell or something like a cloth that hinders your ability to make an audible and understandable noise.

Somatic: This means when you want to cast this spell, you will have to use hand movements. Your hands will need to be free. So you can not be bound or magically restricted when you want to cast the spell. 


Gust of Wind in 5e can dispel Cloudkill. It can also be dispelled by a regular wind or by breaking the spell when you kill the caster. The spell, when not broken or dispelled, has a duration of 10 minutes. However, nothing stops the caster from recasting this spell again. It is not concentration-based, so it remains the full 10 minutes of its casting time, even if another sorcery has been cast.


The school that this spell is part of is the school of Conjuration. It is the school that is known for, well, conjuring things. These can be animals or allies like with the spell Planar Ally, but it is also possible to conjure this fog of deadly gas. It is quite a fun magic school if you know how to make the best use of it, so make sure you read up on it.

Attack Save and Damage

When you are engulfed in the fog of deathly poison, you will need to make a saving throw. Cloudkill 5e will deal damage on the first turn it is cast, so make sure you remember this as a DM and as a player. When you do a successful CON saving throw, the damage is halved. So it will hit you for 20 instead of 40 on average. The damage done by this spell is poison, and it has the poison effect. So do not underestimate the pure damage output this conjuration spell can do. 

Kerem Beyit -Cloudkill 5e
By Kerem Beyit

How good is Cloudkill in 5e? 

So that is quite an explanation for a single spell. However, that says nothing about how good Cloudkill 5e really is. Here is what I think makes this spell great and what makes it less interesting to use in some cases. 

Environmental Combo for Enhanced Effectiveness

It is a good spell, but you can make it much better simply by using it as a combo and having your environment help you. If you read the rules, you will see that the Player Handbook specifically says that the fog moves. It does not expand like a lot of players, and Dungeon Masters think. The fog is going to move 20 feet every turn, so that is pretty slow. 

Closed Spaces Amplify the Impact

If you are using Cloudkill in an open space, it isn’t going to do you a lot of good. However, if you are able to cast it in a closed space, like the lair of a lich, you will do some serious damage to the adventuring group. Since the fog can attack multiple targets, it is possible to take down the adventurers with a low CON easily. Don’t forget; you can double the damage this spell does when you put it in the 10th spell slot instead of the 5th. 

Prolonged Damage Potential

The spell lasts for 10 minutes, so you will do serious damage that is going stack. However, it is not a concentration spell, so you will be able to keep casting other spells while the fog is active.

In conclusion, if you are using this spell, make sure the environment is in your favor. That way, your players won’t be able to escape the slow fog if they are not able to dispel it with, for example, a Gust of Wind or with the whirlwind spell. 

6 ways to use Cloudkill as a DM

1. In a lich’s cave

This is the classic use of Cloudkill in 5e. It is a true staple for a DM who wants to give his players a serious challenge. Be prepared to have a party wipe out if your adventurers underestimate this spell. On the other hand, a party with some experience will see this spell coming from a mile away, so they will be smart enough to counter it with something like a wind spell. 

2. A trap in a closed room 

There is nothing like having a shiny object in the middle of a room that is an obvious trap and having one of your players ignore all logic and forget to do a perception check. This is a great way to scare them or wipe the party in the mid-levels. If you just want to scare them, I would calculate how many hit points the lowest member has and make the duration just long enough to leave them with just a minuscule amount of life left. 

3. In a banquet hall with doors locked

Suppose you want to set the setting for a villain, nothing like crashing a party with Cloudkill. Instead, you can have your allies lock the doors just after they have cast the spell in a room. That way, the weaker NPCs will have no chance if your party doesn’t know how to dispel the spell or open the doors. 

4. As a way to shake off pursuers

If you want to shake off any enemy that is following you or doing chip damage, you can use Cloudkill. Your pursuer will have to walk through it and thus take 5d8 of poison damage. To make your escape tactic extra effective, you can combine this by casting Create Bonfire. This spell will hit them if they wall over it. 

5. Cleaning out a dungeon

Not sure if the room you are about to enter is free of enemies? Do you suspect something is hiding, but your perception check has failed you? Just use this spell, and you will be sure that anything which is hiding is going to get damaged pretty hard. 

6. Stopping an infestation 

Is there some kind of goblin, rat, or mouse infestation going on? Well, it’s time to use Cloudkill to get rid of all of these pesky little monsters hiding away. In 5e, it is a great way to get rid of large mobs that would be dangerous if they are going to try and overwhelm you.  

Cloudkill 5e uses Black and White Dice on Counter

Final remarks about this strong spell

You might have had to deal with Cloudkill 5e already. Then this scenario might be familiar to you. You enter the lair of a lich; the door closes behind you, and all of a sudden, you hear a voice say the spell. If you are familiar with this 5e spell, you know you are in big trouble now. It is one of the strongest opening moves a creature can make if they want to deal serious damage to an entire party.

The best way to summarize Cloudkill in 5e is an overpowered spell in the right location that is underpowered at the wrong place. For example, if you are using the spell somewhere where there is a ton of Wind in an open space, the spell will do anything barely and would be considered a complete waste of turn to cast it.

However, you can cast the spell in an enclosed environment that is around 20 feet radius, like the room of a mansion or a cave. If the spell has been upgraded by putting it in a higher spell slot, like the 9th or the 10th, it has the potential to do double the damage. 

Use CasesDescription
Environmental Combo for Enhanced EffectivenessUsing the fog’s movement in combination with the environment can enhance the spell’s effectiveness. The fog moves 20 feet every turn.
Closed Spaces Amplify the ImpactCasting Cloudkill in a closed space, such as a lich’s lair, can cause serious damage to the adventuring group, especially if they have a low Constitution score. Damage can be doubled by casting it in a 10th-level spell slot instead of a 5th-level slot.
Prolonged Damage PotentialCloudkill lasts for 10 minutes and does continuous damage, allowing for significant cumulative damage over time. It is not a concentration spell, so other spells can be cast while the fog is active.
6 Ways to Use Cloudkill as a DMAs a Dungeon Master, Cloudkill can be used in various ways to challenge players and create interesting scenarios. Examples include: in a lich’s cave, as a trap in a closed room, in a banquet hall with locked doors, as a means to shake off pursuers, for cleaning out a dungeon, and to stop an infestation.

Faq about Cloudkill 5e

Does Cloudkill deal damage in the starting turn when it is cast?

If the target is within the poisonous fog that Cloudkill spawns, then the spell will do damage on the starting turn when it is cast. If the target is not in a fog, it won’t take damage. However, remember that the cloud is able to move 10 feet per turn, so it can cause damage on the second turn. 

Does gust of wind counter Cloudkill 5e

Yes, both whirlwind and gust of Wind are able to dispel Cloudkill. This is because the fog will be dispersed when a heavy wind hits it. Another way to counter the spell is by going to the skies. The fog is heavier than air, so it goes down to the ground. A gust of Wind, or any other wind spell for that matter, is not going to extend the radius of the fog. 

Does the damage from the spell stack?

Yes, the damage of Cloudkill stacks 5e; the same goes for any other editions of DND. This makes the spell very powerful for targets that are not able to escape its radius. In just a few turns, the damage can stack to over 100 hit points easily. This can wipe even high-level adventuring parties that do not have a counter. 

Are zombies affected by Cloudkill 5e

No, they are unaffected. The spell is based on poison damage and zombies, and a lot of other undead creatures and elementals like the Ice elemental are immune to poison damage. So it won’t be able to harm them. This is why a lich so often uses the spell. His zombie and skeleton minions are unaffected when he casts the spell, so they can keep attacking without any problem.

What dispels this spell

There are a couple of ways to dispel Cloudkill in 5e Dungeons and Dragons. The first one is to incapacitate the caster. This will stop the spell. The second way is the caster dispelling it either under pressure or voluntarily. Then there is the third way; this is by just writing out the duration of the spell.

The spell takes 10 minutes to complete, so if you can hang on this long, the fog automatically disappears. Then the final way to dispel it is by using a wind spell. I suggest you use either gust of Wind or whirlwind. These will not make the fog spread but nullify it. 

Cloudkill 5e ruling: How does it work?

The ruling is not that hard. You need to look at what the spell says it does in the rulebook—nothing more, nothing less. The thing most people don’t understand is that the fog does not expand, but it moves.

This means that the 20 feet radius is going to remain 20 feet, but the cloud can move 10 feet from its originating point. Another thing people don’t get is when the cloud starts to deal damage.

Just like any spell, when the spell hits the target, it will deal damage. So when Cloudkill is cast, and the target is within the radius of the fog, it will take damage on the starting turn. The golden rule applies; when in doubt, read the ruling!