In D&D 5e, there a handful of monsters that will instantly kill characters if underestimated.
These nasties have effects, spells, and abilities that can make them absolute powerhouses. If encountered in the wrong area or at the wrong time, it can very quickly result in a character’s death or even a Total Party Kill.
Unless your characters have a death wish, it might be better to tread carefully and avoid these monsters unless you’re absolutely sure you can win!
So let’s get right to it with 12 Monsters That Will Instantly Kill Characters in D&D 5e!
Woe to the adventurer who falls to 0 hit points near a Will-O’-Wisp.
These seemingly harmless floating orbs of light are far more malevolent than one might initially think.
But, considering how they are formed, what else could you expect? In D&D 5e, Will-O’-Wisps are the doomed souls of evil creatures who die in misery or anguish in an area of powerful magic.
So what is so bad about dropping to 0 hit points near a Will-O’-Wisp?
Their Consume Life ability may have a low target as a DC 10 Constitution Saving Throw, but is it really no big deal when the result of failing is instant death?
But, hey, the Will-O’-Wisp gains 3d6 hit points after killing a character in this way, so, you know… I’m sure it’s appreciative?
The Intellect Devourer is a brain with clawed legs that is created by Mind Flayers to work as roaming hunters.
These predatory creatures use their Devour Intellect and Body Thief abilities to consume the brain of their prey and take control of the body.
When the Intellect Devourer uses its Devour Intellect ability, the target must makes a DC 12 Intelligence saving throw. It deals some solid damage, but it’s the other feature of this ability that makes it so terrifying.
The DM rolls 3d6 if a character fails their saving throw. If the DMs result is higher than the character’s Intelligence score, the character’s Intelligence is reduced to 0 and they are stunned.
The Intellect Devourer then uses its Body Thief ability to attempt to take control of the character’s body. This puts the rest of the party in a predicament: do they kill their once-ally?
Being that the character cannot regain their brain after such an attack without the use of a Wish spell, this can go south very quickly for characters who are unaware of the Intellect Devourer stalking them.
Souls who are unable to pass to the afterlife become Spectres. These creatures lash out in anger at any living creature that they encounter.
The Specter’s Life Drain attack deals 3d6 damage to its victim, but it goes beyond that.
The Specter’s Life Drain reduces their victim’s maximum hit points by the amount of damage taken if they aren’t able to beat the Constitution saving throw. When a character’s maximum hit points are reduced to 0, that character outright dies.
As with other monsters on this list, it’s a low DC of 10 to beat the Constitution saving throw to resist the Life Drain, but it’s incredibly important that you do. As a CR 1 creature that can move through creatures and objects, the Specter can very easily result in a character’s death at low levels!
Learn more with my full guide to Specters and Poltergeists in D&D 5e!
The Mummy has a particularly nasty ability by the name of Rotting Fist.
The initial damage of the Rotting Fist isn’t something to laugh at. It deals 2d6+3 bludgeoning damage plus an additional 3d6 necrotic damage.
A CR 3 that pumps out an average of 20 damage a turn while also being resistant to non-magical attacks and immune to necrotic and poison damage is pretty tough as it is. But it gets much worse… so much worse…
The Mummy gets two attacks: one with its Rotting Fist and another with its Dreadful Glare.
The Dreadful Glare may send characters running in fear, but if they fail their saving throw by 5 or more it will paralyze them.
This is when the Mummy eagerly follows up with its Rotting Fist. Not only do they get advantage against the paralyzed target with their hard-hitting Rotting Fist, but a character that fails the accompanying saving throw is cursed with Mummy Rot.
Until this curse is removed, the character loses 3d6 of their maximum hit points every 24 hours. If this curse reduces the character to 0 hit points, they turn to dust being carried away with the wind.
Unless they’re inside, I suppose. In that case, they’re just a pile of dust on the floor.
You get the point.
We talked about the Sea Hag’s Death Glare ability in our Guide to Hags. It’s their signature ability and, much like the other entries in this list we’ve already covered, can be devastating despite a relatively low saving throw to resist it.
You have to give the Sea Hag some credit. Its hideous appearance is what sets off the chain of events that can quickly lead to a TPK.
With her skin coated in patchy fish scales, seaweed hair, and large, fish-like eyes, the Sea Hag takes ugliness to an entirely new level.
A creature that can see the Sea Hag and starts its turn within 30 feet of her first must make a Wisdom saving throw to not be frightened. If they fail, the Sea Hag can use her Death Glare on the frightened character.
Failing to make this saving throw means the character is instantly reduced to 0 hit points.
From there, the Sea Hag may choose to finish the character off by drowning them in the murky swamp waters that they so favor.
The Shadow is deceptively deadly. As a creature with a CR of 1/2, it’s easy to skip past them. But all it takes is one ill-timed encounter for your players to wish that you had kept flipping through the Monster Manual.
The Shadow is able to effortlessly stalk the players’ characters thanks to its ability to easily Hide in areas that are dark or dimly lit. If the party tries to escape from the Shadow, it is able to move through areas with an opening of even 1 inch to stalk its prey.
But it’s the unique way that the Shadow damages characters that make it so dangerous.
When hitting a character, the Shadow reduces their victim’s Strength score by 1d4. When the victim’s Strength reaches 0, they die.
Characters who make Strength their dump stat, like Wizards for example, can potentially be instantly killed in 2 hits from a Shadow. Mind you, as the Shadow is reducing their victim’s strength, it becomes harder for the victim to fight back by swinging their melee weapon.
Even worse, a character who dies this way returns as a Shadow in 1d4 hours.
Swarm of Rot Grubs
Nestled away towards the very back of Volo’s Guide to Monsters is a creature so deadly that it honestly feels unfair. Well… rather, creatures…
Do not under any circumstances let the CR of 1/2 fool you. The Swarm of Rot Grubs can kill an unlucky or unprepared level 20 character almost as quickly as they can kill lower level characters.
The Swarm of Rot Grubs has +0 to hit as they attempt to burrow into the character’s body. If this hits, the character is infested by 1d4 rot grubs.
At the start of each of the character’s turns, it takes 1d6 damage per grub in it as they chew their way towards the victim’s heart.
You have one round that you can use fire to burn the rot grubs out before they are buried too deep to be burned. After that, the party must use a spell that cures disease to get rid of the grubs. However, in all my years of playing D&D I’ve noticed that spells like Lesser Restoration are not commonly kept prepared by many parties.
If the target starts a turn with 0 hit points, they die as the Swarm eats their heart.
Of course, the DM may allow for more drastic options if the character acts quickly and decidedly. I once had a player, upon passing his check to determine what these were, demand that the party’s Barbarian hack his character’s leg off before the grubs could burrow deeper. With everyone looking on in horror, I allowed it.
Needless to say, things got very interesting from that point on.
The entire group also has a phobia of worms now. Even describing earthworms in a dungeon or maggots on old rotted food immediately sees them setting fire to everything around them just in case.
The Bodak is one of my favorite undead creatures in D&D 5e. Its combination of abilities make it disgustingly powerful in the right situation.
For better or worse, an encounter with a Bodak is going to be a memorable and nightmare-inducing fight.
The Bodak has a one-track mind: it wants to destroy all life. These hideous and deformed creatures who were once worshippers of Orcus, the Demon Lord of the Undead, are so hideous that even seeing them can reduce a character to 0 hit points.
A character who fails their DC 13 Constitution saving throw takes 3d10 damage. If they fail by 5 or more, they drop to the ground with 0 hit points.
This means that you have two options against the Bodak: hope that you don’t fail a Constitution saving throw or cover your eyes while you’re fighting it.
Best case, you’re attacking with disadvantage. Worse case, you’re unconscious.
Oh… but it gets so much nastier than that…
The Bodak has an Aura of Annihilation that deals 5 necrotic damage to all creatures who end their turn within 30 feet of it.
So let’s say that the Bodak surprises you…
You fail your Constitution saving throw and immediately drop unconscious with 0 hit points. The Bodak then automatically scores a critical hit against your unconscious body with its melee attack for 2 failed death saves.
At the end of your next turn, the Aura will finish you off with another automatic failed death save.
You have 1 very quick window to get back up on your feet and away from the Bodak before you are once again dropped to the ground.
This can very quickly turn into a vicious cycle that is made even more terrifying if there are other undead nearby that are eager to feast on a fallen character!
Related: The Guide to Bodaks in D&D 5e
The Banshee is crazy powerful and it is not unheard of an entire party dropping to 0 hit points at the very beginning of a fight.
The Banshee’s infamous Wail affects all creatures within 30 feet of her. Any creature that doesn’t succeed on a DC 13 Constitution Save is reduced to 0 hit points. Even if they succeed, they’ll still take 3d6 damage!
At a CR of 4, the Banshee’s potential to knock the entire party unconscious makes her incredibly dangerous to any party.
All it takes is a couple failed rolls to make an encounter with the Banshee an unwinnable fight that will certainly result in the death of at least one character.
As we enter the top 3 monsters that will instantly kill characters in D&D 5e, I think it’s fair to consider all of these among the absolute epic tier of monsters in D&D lore.
While I generally tried to keep the previous entries in this list in a type of ranked order, it’s honestly safe to consider all three of these as tied for first place.
So what better place to start than with the brain-devouring creators of the Intellect Devourers that we discussed earlier?
The Mind Flayer is an absolute icon of a monster.
These octopus-headed tyrants have conquered and enslaved entire worlds with their ruthlessness and terrifying hive-mind intellect.
Beneath the tentacles dangling from their face, a wide and toothy maw waits for the perfect moment to devour the brain of any who are unfortunate enough to find themselves in the Mind Flayer’s grasp.
The Mind Flayer’s tactics are vast, but the general flow is something along the lines of: stun them, grapple them, eat their brain, ???, profit(?), do it again.
With the Mind Flayer’s Mind Blast, all targets in a 60-foot cone must make a DC 15 Intelligence Save or take 4d8+4 psychic damage and be stunned for 1 minute unless they make the save in a subsequent turn.
When attacking with its Tentacles, the Mind Flayer attempts to grapple the character. Once again, if the character isn’t stunned, they have to make a DC 15 Intelligence Save to stay that way.
With the character stunned, grappled, and helpless, the Mind Flayer wraps its tentacles around the creature’s head and deals an incredible 10d10 damage as it bites down.
If this reduces the character to 0 hit points, their brain is devoured and the character is very, very dead.
Get Your Brain Food: Mind Flayers in D&D 5e
We’ve talked about the Lich in some detail before.
These mages have mastered the force of death to unlock the secrets of eternal life (or some semblance of it.)
Look, the Lich has no shortage of ways to fundamentally destroy a group of pesky adventurers who are brave enough to disrupt their work.
But there is one spell that puts the Lich on this list. Just one eensy-weensy little spell by the name of… Power Word Kill.
This spell has one of the shortest descriptions in the entire game which adds to the sense of finality about it.
Does the target have less than 100 hit points?
Just like that. No save or anything.
The Lich can only use this once in an encounter since it’s a 9th level spell, but, with their massive intellect and ruthless nature, you can be sure that the Lich will use this in a way that is guaranteed to hurt the most.
We couldn’t end the discussion about monsters that will instantly kill characters without mentioning a long-time fan favorite!
One of the greatest undisputed icons of the D&D Monster Manual is the paranoid and megalomaniacal Beholder.
Not content with just one method of instantly killing characters, 3 of the Beholder’s 10 eye rays are capable of this.
The Beholder’s Eye Rays
These rays have a DC of 16 to resist and they are not something to take lightly!
The Beholder uses its turn to randomly fire three eye rays at the party. Then, it can take a total of 3 legendary actions between players’ turns to fire additional rays. In a single round of combat, that’s 6 eye rays flying at the party.
With 3 of the 10 options potentially meaning instant death for a character, you will be able to feel the charge of tension at the table when the party begins combat.
First, there’s the petrification ray.
If a character is hit with this one, they have one more chance to resist the petrification on their next turn. If they fail that one as well, they are turned to stone until a Greater Restoration spell (or something similar) is cast on them.
Of course, you’ll have to cast this spell when you’re sure that you’re free from the Beholder’s antimagic cone while also hoping that it doesn’t decide to just blast your friend’s statue to kingdom come.
Then we come to the Death Ray.
Getting hit by this deals 10d10 damage and instantly kills a character who drops to 0 hit points as a result. This is bad, but pretty on-the-nose in terms of how it works.
But then we come to the one that people most fear from the Beholder: the Disintegration Ray.
The Disintegration Ray doesn’t deal as much damage on average as the Death Ray, but 10d8 is nothing to sneer at!
What makes this particularly terrifying is that a creature reduced to 0 hit points by this attack is turned into a pile of fine gray dust.
The random nature of the Beholder’s attacks actually serve to make it more terrifying, I think. While the DM isn’t able to choose the rays, that also means that they aren’t able to take it much easier on the party if they’re feeling sorry for the almost-certainly terrified adventurers.
Conclusion – 12 Monsters That Will Instantly Kill Characters
So there you have it!
12 absolutely terrifying reasons that your players will never sleep again and their characters may never wake up.
It’s not surprising that this list is pretty heavy with Undead creatures. If you’re looking to use some of these to dastardly effect, you should also check out our article on How to Run Horror Games in D&D.
When planning an encounter involving these creatures, Dungeon Masters will want to spend extra time analyzing all of the details of the encounter.
Terrain, additional monsters in the combat, and resources that the party will likely use on the way to this encounter should all be factored in.
Because the ability to instantly kill characters is so powerful, it can take no time at all for combat to quickly turn against the players.
Just always remember one key point of advice when using these monsters in your games: Don’t forget to tear up the character sheets.
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