5 Underrated D&D 5e Monsters (from Just the Monster Manual)

Today I want to talk about something simple that can make a big difference at your table—using monsters your players don’t already know inside and out. And if you’ve been here before, you’ll know that simplicity is my jam because I want a certain experience but I also don’t want to put in inordinate amounts of time and money or in DnD’s case, scouring a million splatbooks or pulling in third-party stuff. This is all just from the Monster Manual.  

So here are five monsters I think could do wonders at the table. They’re easy to slot into a game, but they still give you that 'wait, what?' moment.

1. Grick

This one’s such a sleeper. The Grick is quiet and camouflaged, and absolutely deadly in the right terrain. It’s not flashy, and I think that’s why it gets skipped over. But that’s what makes it deadly - it’s basically an ambush predator. The deadliness comes from the fact that it’s very hard to sneak up on - especially because it’s already hidden so like you don’t even know you’re supposed to be looking for it. It’s not supposed to be flashy. It’s supposed to be sudden.

Stick it in a cave or ruin and let your players walk into it like a trap they didn’t realize was a trap. It’s basically a dungeon ambush that doesn’t need any moving parts.I put it in the path my party was travelling - a wooded foresty area where all nature starts to kind of look the same after awhile. Also I’ve found that DND combats kind of thrive with the action economy  managed so you’re gonna want at least two of these. If this is meant to be a tough encounter, have one less than the party. So if you have 4 PCs, there are 3 Gricks. If you have 5 PCs, there are 4.

2. Chuul

I love a good monster moment. Like anything I can describe as having dripping saliva, I’m on board. And Chuuls deliver. They’ve got that classic monster feel - claws, tentacles, mysterious ancient intelligence - but what I really like is that they’re built to serve something worse. In the Monster Manual, Chuuls are described as servitors created by the aboleths, and even after the aboleths' empires crumbled, Chuuls still follow their old programming: they serve powerful aberrations, obey psionic commands, and sometimes lie dormant for centuries waiting to be reactivated.

So you can use a Chuul as is or to hint at a bigger arc: some far realm corruption, an ancient aboleth, whatever. They can be a breadcrumb and a boss fight in one. Like I said though, action economy will take you far with DnD combat so ideally you want this guy and a few mobs or two of them, and because they are solitary, maybe make them parent and child or mates.

3. Shadow

Shadows mess with parties in a way that feels personal. Every time they hit, they drain Strength - beyond just dealing damage. So your tanky frontline fighter who can usually just soak up hits five minutes ago, suddenly can’t even lift their weapon. And your spellcasters? A lot of them dump Strength entirely, which means a couple bad rolls and they’re unconscious without ever taking a hit point of damage.

And also - if a creature dies to a shadow, they come back as another shadow under the DM’s control. Now the thing that killed you is wearing your face, and it’s still hungry.

This is what I mean when I say shadows feel personal. Like at some point you’re just being mean.

Shadows totally shift tone, just organically because they make players second-guess their usual tactics. Suddenly it’s not about pure damage output - it sort of demands something a little more intentional and tactical and maybe remembering that old +1 sword someone left in the bag of holding.

My point is, whoever it goes after it’s going to kind of rattle the party a little, forcing people to think differently about their gear, their spell choices, and honestly, their survival. And that can be pretty cool.

4. Will-o'-Wisp

I think people forget how mean these things are. They’re fast, they go invisible, they’re immune to a bunch of common effects, and they feed off dying creatures like fucking carrion birds. 

If you’re running anything kind of foggy and atmospheric - moors, swamps, ancient ruins, or basically anything in the feywild, Will-o'-Wisps can turn a slightly tense travel day into a nightmare. Sometimes there’s nothing better than saying to your players, ‘Your instincts were absolutely right about not being safe.’

Because Will O’ Wisps are predators but they’re not front-line monsters. They’re opportunists. Just a few failed Perception checks and someone’s wandering off, and now the group has to decide if they risk splitting up, or following that flickering light.

I love that you can drop them as set dressing into what’s basically a filler travel day or a classic spooky location and suddenly your party’s burning resources trying to just land hits on something that can go invisible as a bonus action. So here’ s hoping someone has something magical that doesn’t need line of sight. That makes them annoying, but what really makes them dangerous though, is their ability to sense when a creature is at 0 HP and use that to heal themselves. They don’t just kill - they feed. 

And the bonus is: they look beautiful and harmless. They’re basically just fireflies, right? Nope… 

So yes, it’s a low level creature. But in the right context, as a small group, with even a little terrain advantage, it can absolutely wreck a party that isn’t ready for it.

5. Quadrone

This is a weird one, and you might reflexively think this robot looking thing doesn’t fit in your medieval fantasy but it’s exactly that reason it’s such a great one to us. Most players have no context for them - I certainly didn’t and I consider myself fairly “into’’ tabletops.

So in the lore, modrons are beings of pure logic from a different plane where everything is order, hierarchy, and math. Quadrone - one of their varietals - are basically middle managers. Messengers. Observers. They’re not here to fight. They’re here because something bigger is in motion.

What I love about dropping a Quadrone into a game is that it doesn’t have to make sense right away. It’s not hostile. It’s not helpful. It’s just here and probably doing something that seems weird - cataloguing rubble, measuring the velocity of a falling trap, counting how many doors are open... And the party has to decide what to do with that. Because it isn’t a threat - until it is. It could be that they said the wrong thing so suddenly its ready to defend itself from this group of threats, and calling for reinforcements. Or until the party realizes it’s relaying everything they say back to something with a lot more power and a lot less respect for free will.

Sometimes you don’t need a monster to start a fight. 

You’ll notice none of these are high-level monsters or need a whole custom stat block. But each one can add something strange, interesting, or even unsettling to your game just by showing up.

And for me, that’s the real magic of monster design - it’s not about power. It’s about how the monster affects the tone of the scene.