D&D 5E Concentration mechanic can ruin plots in adventures

[Helldritch]

Last night I took one of my old adventure that I wanted to adapt to 5ed and I got a slap in my face. This adventure was no longer possible with the concentration mechanic!
The adventure was called The Dungeon of Excapode the Mad. Here is the back story. A mad enchantor decides to frame the leaders of GreyHawk city into giving him money. Naturaly, his first demands are debunk so he decides to kidnap the concubines of a few city officials to force the hand of the city's leader. Unfortunately, the chosen victims are worth next to nothing so it is their husbands/father/lovers which hire the players to deal with the mad mage.

Now, this mage is utterly crazy. He charmed a few monsters and two bands of adventurers to work for him. Monsters would be locked into a room where the players would have no choice but to get through them to advance and so on. The problem is with the charmed adventurers. One is made up of evil type characters but the second was made up of "good" or at least non evil NPC. The hard part was not to liberate the hostages but to do it without killing the good guys.

With the concentration mechanic, it is now impossible to charm that much people/monsters into working for you. Giving such a power to an NPC would not be my style (and I would not give him an artifact). Making the evil group willing pawns of Excapode would work but how to make it so that the good NPCs work for the mad mage without breaking the rules by which the players must abide? So far I saw nothing that could make it work without giving too much powers to Excapode, which would make him a much higher threath than he should be.

Any idea that would both respect the premisses and the new rules?

 

[iserith]

Write a unique trait into the mage's statblock that allows him to do the thing you need him to do. Easy peasy.

 

[abirdcall]

NPCs don't follow PC character creation rules.

This is not like 3e.

They have whatever powers you want to give them.

Remember that PCs also have special powers that are represented by class abilities (and sometimes feats).

NPCs just have special powers that aren't covered in PC creation rules.

 

[prabe]

There's no limit on how many victims a vampire can charm. Introduce some McGuffin that enables your BBEG to emulate that? Find some other effect? Glamor bards can charm a lot of people at once, though there are other limitations, IIRC. If it's a McGuffin it just breaks before the party can use it, unless of course you want them to have it (which seems like a very bad idea). Write up a Mass Charm spell (if there's not already one that's escaping my memory)? Sounds as though you're reluctant to hand-wave, but that's always an option.

 

[Dausuul]

Any idea that would both respect the premisses and the new rules?

Mass suggestion can hit up to 12 targets, has a 24-hour duration, and does not require concentration.

 

[Seramus]

Mass Suggestion and a Vampire are the easiest way to keep your adventure RAW, besides just handwaving the issue.

 

[tommybahama]

Staff of charming plus high charisma. Think Charles Manson with a bag of weed.

The charmed creature regards you as a friendly acquaintance. When the spell ends, the creature knows it was charmed by you.

So after an hour the creature realizes what the Mad Mage has done, but that doesn't mean they automatically regards him with hostility. Au contraire, with his high charisma they probably regard him even higher.

 

[happyhermit]

All of the above, or he found a way to concentrate on multiple spells... but it made him insane.

 

[toucanbuzz]

As @ad_hoc points out, NPCs don't follow the same rules as player characters. For example, my players just went up against Tamoachan's "martial artist adept," aka monks. But these monks could choose, on each of 3 hits, to stun, knock down, or disarm. Pretty powerful, and not an option for PCs.

Just have this guy use whatever charm mechanics you need: 24 hour duration, 1 week duration, no limits, and so on. He's a BBEG and he's going to have powers the PCs will never have.

 

[Oofta]

As others have said. He's an NPC and has access to a spell that the PCs do not.

He has a minor artifact that allows him to charm multiple people. Unfortunately he also "hears" the voices of all the people he's charmed in a distorted way that makes him crazy.

He has special ritual to mimic the powers of a vampire which has also made him unstable.

He's forced a vampire to work for him, or the vampire is actually the real bad guy and the wizard is a pawn.

So on.