I ran the Shackled City adventure path when it first came out in 3.0/3.5 (hard to believe that was more than 10 years ago), and recently started running it for a new group but converted to 5th edition and heavily modified to fit into my homebrew world (for example, not set in Cauldron). I'm using the assembled compendium and am about to start prepping for the second adventure in the path -- Drakthar's Way. As you probably know, one of the hallmarks of the adventure path was its extensive use of templates, especially when layered together with unconventional races. That's less doable, I think, under 5E rules and, regardless, it's not the flavor I'm going for. 

In the upcoming adventure, I'm thinking about using wererats instead of goblins as Drakthar's minions and changing Drakthar's base to be the sewer underneath the city in which I'm setting the campaign. I'd like to drop both the bugbear and vampire aspects of Drakthar (though I'm open to keeping the vampire part). I'd probably bump him up to a CR 6, as the players likely will be 4th level when we start the adventure. Any thoughts on a good leader for a gang of wererats terrorizing a city from the sewers below? 

Keith,

Are you looking for a creature from the Monster Manual, or are you willing to build an NPC and just looking for an idea for that NPC? Because if you just want an NPC I might have a couple of ideas but I don't want to waste your time if you are looking for a Boss monster. Which I might be able to help there as well.

Drop me a line and let me know if you want/need any help

J

Thanks for the response, Auberginian. Drakthar is the boss monster of the second adventure in the path. After some further thinking, I think I might keep the vampire element (but de-powered, given the level of the adventurers) and instead of a bugbear, as he currently is, making him a drow, which fits a bit better with campaign. I'd be curious to hear what you were thinking, though, as I'm open to other ideas.

Well my first thought was a wererat with some arcane powers, perhaps a warlock or something similar. But after a quick review of the module, have you considered a Vampire Spawn which is a CR5 monster. If your party has 5 or 6 characters you can add some additional arcane powers to the vampire. Or perhaps you can build a vampiric wererat which may be a better fit thematically.

I had considered making him a Vampire Spawn given the CR, but I wanted to be able to maintain the story element that he had dominated (though I guess that should be "charmed" now) his way to becoming leader of the pack and to controlling various other NPCs in the adventure. So that's why I was thinking maybe just a de-powered vampire. The warlock idea is a good one, especially if there is a way to do something similar to charm/dominate with those abilities. Our bard is about to multiclass warlock with Tharizdun, the Chained God, as his patron (I'm replacing Adimarcus with Tharizdun), so I could tie into that too. I think keeping him a wererat makes sense as well. Worst case scenario, I could just create a magical item that has an effect similar to the charm ability of vampires, and give that to Drakthar, and make him a wererat warlock.

I see no reason not to give him the charm ability of a full vampire, just drop the DC to 13 or 14.  He's your character you can make any changes you want to it, bump his charisma up a bit to show he is charming.  Also consider giving some basic legendary actions to the character, not as necessary if you have a bunch of supporting enemies in the fight with him.

Mr. Hero is correct, you can do anything you like, so the best advice is do what fits the best for your game. There are many ways for someone to be "dominated" that don't require magic. As Hero suggested, said villain could be very charismatic and be a master manipulator, using persuasion, deception, and intimidation to get others to do what he wants. Or perhaps he does have a magic item, however, if you introduce a magic item be prepared for your PCs to have it when they defeat the villain. I know there are ways to make it so the PCs don't get the magic item but if you aren't subtle about it, then it comes across as a DM screwjob. Of course, we already talked about the idea of the monster with a PC class, I mean the guy wasn't always a wererat or vampire. I mean I sort of like the idea of some weasely character working his way up the food chain and no one can figure out how, similar to how the TV series Gotham did the story arc of the Penguin in the first couple of seasons. Just a thought.

Thanks, guys. All great ideas. I'm leaning towards nerfed vampire, but I might still go with warlock. If I were to introduce a magic item and the PCs were to obtain it, my inclination would be to make them pay a price. Perhaps it's a collar of the vampire or something, where it gives you charm abilities, but you suffer some vampire sensitivities. Just spit-balling here.

I've been thinking about converting Shackled City to 5th edition also, though I would probably keep it in Cauldron. I would love to see what you came up with before I start. 

I ran Shackled City when it came out, just started a D&D club at school, and adjusting it for 5e. The kids LOVE the city of Cauldron, mostly because it seems like a real place, not just some generic town.

So far, I’m building NPCs, I’ll post some stats of those. I also have some player handouts I’ve made. Since most of the players are brand new, I set up a simple adventure for them to learn the basics — the citizens of Cauldron post requests for jobs, and the PCs need to get certified as adventurers to take the jobs. Right now the players are in an encounter where they “just need to get across the room to the other side”.    

I plan to use a lot of the maps, traps, and lore just as it is given in the original story. For monsters, I’ll use 5e similar and adjust as necessary. Other adjustments I’ll make as we go along.

Flyingmatthew, hope we can share resources! 

Just doing my part to save the world, M

is this thread still alive?

Not really, but I am running my version of SC, we are about to start chapter 2. Whet do you need?

Hey FlyingMathew,  I was hoping you may be further along and potentially willing to share your 5e conversions for this campaign . Would this be possible?

Sorry, I've only gotten through Chapter 2 and a little bit of Chapter 3. If you want anything from chapters 1 & 2, let me know.