How does my BBEG control his army of rats?

[Dralnu]

I have a free adventure coming out soon. Just figuring out stats n' stuff.

Premise: One-session adventure for levels 1-3 (details on how to scale). The PCs are tasked with clearing out a tavern cellar of rats, specifically destroy its source. What appears to be a simple task turns into something much more daunting as they discover a secret undeground cave network populated by vicious mutant rats, which are under the control of a crazed alchemist calling himself The Rat King.

The Rat King has been using his alchemy and low-level magic to make mutant rats of all sorts: half-dragon rats that breath fire, "baneling" rats that roll into targets and suicide explode, psychic rats with telepathy, sonic rats, etc.

The big thing I need to make work, however, is I want the PCs to discover a way to control the rats (one at a time). This lets them solve optional puzzles or defeat encounters in alternative/easier ways. For example, if they control the spider-rat, it can access a tiny passage in the ceiling + pull a lever to open a door. Or they can use the sonic rat that deafens affected enemies for 1 minute, which blinds the big cave full of darkmantles that rely on echolocation. And on.

The question is.. how do I let the PCs do this? Is there a spell they could find that would do what I need, or do I need to invent some completely new mechanics?

[Temperjoke]

I have a free adventure coming out soon. Just figuring out stats n' stuff.

Premise: One-session adventure for levels 1-3 (details on how to scale). The PCs are tasked with clearing out a tavern cellar of rats, specifically destroy its source. What appears to be a simple task turns into something much more daunting as they discover a secret undeground cave network populated by vicious mutant rats, which are under the control of a crazed alchemist calling himself The Rat King.

The Rat King has been using his alchemy and low-level magic to make mutant rats of all sorts: half-dragon rats that breath fire, "baneling" rats that roll into targets and suicide explode, psychic rats with telepathy, sonic rats, etc.

The big thing I need to make work, however, is I want the PCs to discover a way to control the rats (one at a time). This lets them solve optional puzzles or defeat encounters in alternative/easier ways. For example, if they control the spider-rat, it can access a tiny passage in the ceiling + pull a lever to open a door. Or they can use the sonic rat that deafens affected enemies for 1 minute, which blinds the big cave full of darkmantles that rely on echolocation. And on.

The question is.. how do I let the PCs do this? Is there a spell they could find that would do what I need, or do I need to invent some completely new mechanics?

Well, The Rat King has mastered controlling all of them by himself, but what if he had prototype wands from earlier experiments with controlling individual types. He might have them meticulously labeled and stored for safekeeping.

[Mr.Moron]

Let them come up with how they control the rats, assuming they reach the conclusion that's what they should do.

If they come up a with a stupid idea "Let's throw them a party, rats love parties they'll work for us" give them an easy INT check to know the idea has no chance of occuring.
If they come up with a plan that seems plausible, but a long shot "Let's capture a rat, draw the blood and reverse-engineer the alchemy", make it take a considerable amount of time and have hard checks invovled.
If they come up with a plan that seems clever, themeatic and likely to you make it simple to accomplish and have easy to pass DCs.

In other words you don't have to come up with a correct answer ahead of time. As the PCs attempt solutions you can dynamically assess how reasonable that approach is and assign the DCs and require mechanical steps as you go along. That's a much easier proposition than coming up with an ideal solution, then trying to think of ways to lead them to it or account ahead of time for every case they might try.

[hymer]

While I generally agree with Mr.Moron, I think adding in a pre-existing way to do it is a good idea. If they use that, fine. If they come up with something else, adjudicate that and have it work if and in the way it seems it should work.

Finding some old notes, and the suggestions planted in the rats' brains along with their trigger phrases, could do the trick.

[Sigreid]

You say he's an alchemist. Wouldn't it make sense that he has a few extra potions around that he uses? Or the recipe for making such a potion? Such a recipe could be a fantastic reward for success for a cleaver party.

[Ralanr]

Pipes of the sewers?

[Madbox]

Maybe an awakened rat who acts as a lieutenant for the BBEG? One that's still has a very animal-like mindset, so that he could easily be bribed with a few days worth of rations.

"Master says you go no further!"
"You look hungry. Here, would you like some bread and cheese? Maybe a bit of beef jerky?"
"...Master hasn't fed Nibbles yet today... Fine, you pass."

[Lonely Tylenol]

Pipes of the sewers?

Pipes of the Sewers.

[Dralnu]

You say he's an alchemist. Wouldn't it make sense that he has a few extra potions around that he uses? Or the recipe for making such a potion? Such a recipe could be a fantastic reward for success for a cleaver party.

This is my favorite option! I ended up doing something similar for my playtest version, but I'll have to refine it for when I write it up. They find a recipe for controlling rats and a couple vials of it for the dungeon. Anyone can use it. Then they have a momento going into future adventures and potentially control future vermin they come across.


While I generally agree with Mr.Moron, I think adding in a pre-existing way to do it is a good idea. If they use that, fine. If they come up with something else, adjudicate that and have it work if and in the way it seems it should work.

Finding some old notes, and the suggestions planted in the rats' brains along with their trigger phrases, could do the trick.

I need a pre-existing way specifically I want to write this up as an adventure module. I do agree that you should let the players figure out alternative methods if they make sense.


Pipes of the sewers?

I don't get it?


Maybe an awakened rat who acts as a lieutenant for the BBEG? One that's still has a very animal-like mindset, so that he could easily be bribed with a few days worth of rations.

"Master says you go no further!"
"You look hungry. Here, would you like some bread and cheese? Maybe a bit of beef jerky?"
"...Master hasn't fed Nibbles yet today... Fine, you pass."

This is awesome too! I will be adding this :)


I ran a playtest of this dungeon and it went very well, the PCs picked up every nugget of information that I hoped they would, including that they could control the rats. Unfortunately, the party's druid, aware that these rodents were unnatural creatures mutated through alchemy, refused to allow the vermin to be used and put them all down as an affront to nature.

I'll go with the potion + recipe suggestion. They find it on the way to the confrontation with the alchemist. They'll also come across the alchemist's awakened familiar as suggested, which they can bribe for information.

Lovely! Thanks guys! I'm excited to write it all up :)

[Ralanr]

Pipes of the sewers is a magic item that can control vermin.

[Squibsallotl]

The big thing I need to make work, however, is I want the PCs to discover a way to control the rats (one at a time).

Speak with Animals and Prestigitation. The latter cantrip allows you to flavour an item of food, talk to the rat to figure out what its favourite food is, get a bit of bread or cheese and flavour accordingly. Suddenly you have the best bribe in the world, from a rat's perspective.

This could be how the Rat King gained their allegiance in the first place, and he might leave scrolls or potions with these spells around for the party to cast (or if you already have a wizard and/or druid, in the party, he might just leave his notes around for them to read and then cast those spells themselves).

[JumboWheat01]

Promise to lead the rats through a victorious war against the cats of the land. That should get them to co-operate.

[Lonely Tylenol]

I don't get it?

Pipes of the Sewers (DMG, p. 185) is an instrument that controls vermin. Think "Pied Piper of Hamelin", only... No, actually, that's exactly what it is: the Pied Piper's magic pipes. It does exactly what you're asking for, and has been a staple item of D&D for decades.

[solidork]

Pipes of the Sewers (DMG, p. 185) is an instrument that controls vermin. Think "Pied Piper of Hamelin", only... No, actually, that's exactly what it is: the Pied Piper's magic pipes. It does exactly what you're asking for, and has been a staple item of D&D for decades.

Actually he is asking for a way for the party to learn to control some of the rats to solve puzzles.