D&D 5E Need some good "guardian" monsters for a treasure vault (4th lvl group)

[Astrosicebear]

As a general adventure design thing I'd be a little wary of the solo boss style encounter. Some classes are quite good at putting the whammy on a single bad guy without legendary abilities. Lean towards one biggie with the option to spawn/bring in more fodder or mid range trouble if the fight turns into the PCs whittling down HP while the big baddie is neutered. Until the DMG it's probably best to leave yourself room to adapt the difficulty on the fly.

I agree... although 5E seems to be better in this regard. Even though monster CR matters much more, theres not nearly as many save or suck encounters on either end. Seems 5e is more slobernocker, less holy hand grenade.

But any memorable encounter is a good set piece... you can turn a low level enemy into a fearsome foe by including its own lair or mechanics.. What if there was just some skeletal dwarf in this room, but the room itself was a trap and the skeleton activated lava pits or acid vents.

Or what if there was no monster until the treasure was touched... then the room slowly fills with lava as the evil monster is slowly revealed behind a stone wall.

 

[Derren]

Backstory:

I'm looking to build a sweet encounter for four characters of 4th level. I need some guardian(s) that will protect an ancient dwarven treasure vault. The dwarves would've spared no expense to keep their treasure safe. Any suggestions for what could be suitable guardian(s) would be greatly appreciated as my brain is currently running blank!

As the dwarves had an artifact which imbued things with magic golems and other animated objects are an obvious choice. An army of high quality iron, adamantium (no expenses spared), etc. golems.

 

[Celebrim]

I'll second the Spectator - classic D&D treasure guardian.
I'd also be considering something like an Iron Cobra.
I've also been fond of Caryatid Columns.

There would also likely be elaborate mechanical traps of various sorts. Dwarves go in for that sort of thing. For a 4th level party I'd make it a combination of working, destroyed, and malfunctioning traps and try to build the flavor that this used to be a lot worse than it is now. For example, in one low level dungeon I had a corridor filled with already triggered upthrust spear traps, several of which had the remains of prior victims impaled on them. Only a few of the 100 or so original traps remained untriggered and in a functioning state.

I also tend to like the notion of animated weapons - Tomb of Horrors style - for the sort of protections dwarves would place on their stuff. A dozen animated battleaxes flying off the walls has an image I like.

Pit traps at this level are pretty much a must. No party should ever obtain high level without at least some of its members having to be fished out of pits.

In my own game, there might be some sort of guardian spirit that had pledged to protect the vault. Depending on the context this might be anything from a 4th level Dwarf fighter with various templating to represent the spirit of an ancestral champion, to an Archon, to medium earth elemental, to a giant fiendish mole rat with flaming eyes come to claim the soul of the thief for Abbathor (using fiendish dire weasel stats). Pretty much anything that you could get from something like monster summoning III (at least in 3e) would be on the menu.

 

[the Jester]

You could convert the dwarf ancestor, a somewhat obscure 3e monster that was basically a statue of a revered dwarf ancestor of the clan that could become animated by the ancestor's spirit to defend its dwarvish dwarfiness. Sounds perfect, though- as I said- it needs conversion.

 

[Delandel]

How about the Flameskull from the Basic DMG? It is CR4 and its flavor text specifically states that it is placed to guard treasures and the like.

Just to reiterate, the CR of a monster is now an indication of what is the earliest level you can introduce them to the party. Adding them before that could lead to several one shot takedowns of the PCs. Just a couple of days ago, a I had a Giant Crocodile (CR5) come within 1hp of knocking the level 5 rogue from full hp to unconscious with 1 bite attack.

Flameskull is a great idea but this homebrew is supposed to follow after Lost Mines of Phandelver. In fact, I'm aiming to publish this as a free module from levels 5 to ~7ish, if possible.

As a general adventure design thing I'd be a little wary of the solo boss style encounter. Some classes are quite good at putting the whammy on a single bad guy without legendary abilities. Lean towards one biggie with the option to spawn/bring in more fodder or mid range trouble if the fight turns into the PCs whittling down HP while the big baddie is neutered. Until the DMG it's probably best to leave yourself room to adapt the difficulty on the fly.

Ugh, right?! My PCs have a knack for obliterating my big evil boss before I can do anything cool. The barbarian frenzies and suddenly my boss is missing 40+ health, goodbye!

Good point. My guardians will be in multiples. Maybe I'll even toss in a semi-difficult encounter right before to bait out some of the PCs nukes.

 

[Tormyr]

Flameskull is a great idea but this homebrew is supposed to follow after Lost Mines of Phandelver. In fact, I'm aiming to publish this as a free module from levels 5 to ~7ish, if possible.

Sorry, your first post and thread title say 4th level party. You might want to edit that so people adjust the CR of the enemies they are suggesting. Some people have already suggested some CR5-7 enemies which could be interesting. Which level would the party encounter this guardian(s)? 5,6 or 7?