Dungeons & Dragons is one of the most renowned tabletop RPGs in the world. Its fantastical universe is brimming with wonders each pushing the bounds of imagination further and further. Of these otherworldly creations, however, none are as marvelous or as inventive as D&D's expansive list of monsters.

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Monsters act as obstacles meant to challenge adventurers and impede their progress. At lower levels, these creatures should push players without significantly exceeding their capabilities. Most low-level monsters are reasonably troublesome; however, some are capable of wiping out low-level parties and even dispatching high-level characters.

10 Rust Monster - Challenge: 1/2

While many of D&D's monsters attack players out of spite the Rust Monster does so simply for a meal. This bug-like beast lives to corrode metal and feast upon its rust. So, while the Rust Monster is usually a docile creature, it will assault players relentlessly should they possess any sort of food.

Even though the Rust Monster's stats are unimpressive its action to corrode metal is devastating. Any metal object - including weapons and armor - that it touches will take permanent damage and may even break. This is especially crippling against martial classes such as Paladins and Clerics that heavily rely upon their gear.

9 Cockatrice - Challenge: 1/2

Derived straight from English mythology, the Cockatrice is a terrifying and deadly amalgamation of animals. This beast possesses the features of a lizard, a bird, and a bat making it a frightening yet simple foe. However, the Cockatrice's appearance is its least threatening feature as its bite can turn a victim's flesh into stone.

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While its petrification only lasts a day, it provides Cockatrice an effective way of removing players from battle. By petrifying one or more troublesome characters, flocks of Cockatrice can pick off the rest without difficulty. This action is exceedingly useful against ranged attackers that prevent Cockatrice from attacking then flying away.

8 Swarm Of Rot Grubs - Challenge: 1/2

There are many tiny monsters in D&D, yet none are as lethal as the Swarm of Rot Grubs. Despite their size, even one of these flesh-eating grubs can spell doom for low-level characters. Swarms of them, however, pose a threat to high-level adventurers, monsters, and essentially anything they can sink their teeth into.

Swarms of Rot Grubs burrow into characters and slowly eat away at their flesh progressively damaging them. If they linger, Swarms of Rot Grubs will devour the player's heart killing them instantly. Although characters can deal with Rot Grubs in a variety of ways, an overwhelming number of them can easily kill one or more characters.

7 Shadow- Challenge: 1/2

Shadows in D&D are far more sinister and dangerous than they appear to be. They are incorporeal undead beings of negative energy with only one purpose, to annihilate all living things. While Shadows lack any formidable traits, they can easily follow characters anywhere and steal their life energy.

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Shadow's amorphous form and action to drain Strength make them relentless party killers. Aside from well-lit areas, there is almost no space that a Shadow cannot reach making escape a near impossibility. Moreover, they can drain a target's Strength, and kill them should it reach zero. Even characters like Barbarians and Fighters will falter against the Shadow's crippling action.

6 Kobolds - Challenge: 1/8

While seemingly unimpressive and weak, Kobolds prove to be more than challenging when in numbers. They are clever lizard-like humanoids with an affinity for cooperation and trap-making. A single Kobold may not offer any difficulty but with allies, it can annihilate low-level parties and slaughter high-level characters.

If an ally is nearby - Kobold or not - they will have an advantage on every attack. This allows Kobolds to carry out relentless assaults against players dwindling their fortitude. Moreover, if parties enter a Kobold den, they risk facing not only overwhelming adversaries but debilitating traps as well. Overall, Kobolds are effective party killers, especially when encountered in their domain.

5 Intellect Devourer - Challenge: 2

Intellect Devourers are the sinister creations of D&D's most malevolent otherworldly beings, the Mind Flayers. Originally, the brains of thralls, a horrible ritual made them vile psionic servants. Like their masters, Intellect Devourers possess the same power capable of bending the minds of mortals.

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The Intellect Devourer can weaken a character's mind reducing their Intelligence to zero leaving them a mindless husk. Upon clearing the target's mind, the Intellect Devourer will consume its brain and take control of its body. This not only kills a character but allows the Intellect Devourer to use their body against the party as well.

4 Flameskull - Challenge: 4

Simple yet malevolent, the Flameskull is an unyielding and merciless monster. This disembodied skull is the result of horrible experimentation with dark arts that turned it into a sadistic undead creature. Although the Flameskull appears to be an uninspiring creature it is among the deadliest low-level undead monsters.

The Flameskull possess an innate ability to cast spells and the persistence to continue living - or unliving - even after death. Its memory, although mostly erased, grants it spellcasting allowing it to cast devastating magic including the renowned spell Fireball. Additionally, the Flameskull will revitalize itself within an hour unless its remains are purified allowing it to easily wither away parties.

3 Banshee - Challenge: 4

Dreadful and unforgiving, Banshees are undead specters that have terrorized those unfortunate enough to discover them. These sorrowful ghosts were once beautiful female elves cursed for exploiting their beauty for personal gain. Banshees, overall, are deadly undead monsters yet their most lethal feature is their piercing cry.

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Once per day Banshees can unleash a far-reaching and ear-shattering wail to all within its vicinity. Characters within range who fail to endure the mournful screech will suffer devastating psychic damage. Even if most players survive a Banshee's vicious cry its corrupting touch can easily finish them off. This forsaken spirit is an effective party killer that is difficult to combat.

2 Roper - Challenge: 5

Bearing the resemblance of stalagmite/stalactite, the Roper is a large monstrosity capable of widespread destruction. This cave-dwelling creature bears six far-reaching tendrils and a gaping mouth. The Roper's affinity for ambushing allows it to gain an advantage over foes yet even when revealed it remains a near-insurmountable threat.

Using its fifty-foot tendrils it can grapple up to six characters at once. Upon grappling players, they become immobile, and the Roper will reel them in to its deadly jaws. Alternatively, if it roots itself on a high elevation, it may drop players possibly resulting in a TPKO. Even if the Roper loses its tendrils, they will regrow allowing it to continue its assault and finish off players.

1 Bearded Devil - Challenge: 3

The Bearded Devil is a peculiar adversary from the depths of hell capable of handling low-level parties of four alone. As the name suggests this devil's beard is of great significance, in fact, it is by far its most lethal weapon. Using its beard and its glaive, the Bearded Devil can unleash a flurry of attacks each causing debilitating side effects.

The Bearded Devil's beard possesses poisonous barbs, and its glaive can inflict hellish wounds upon characters. Its beard can impose a horrible poison that not only gives a disadvantage on attack/ability checks but also prevents healing. The Bearded Devil's glaive, moreover, can create grievous cuts that worsen with each hit. Each of its attacks can dispatch low-level characters within minutes.

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