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Simple Ways to Structure a D&D campaign (part two)

Updated: Feb 5, 2023

This article is part of a series of posts on how to create a simple campaign structure that is easy for GMs to write and run. You can check out part one here.

In last week’s post we looked at how GMs can create a strong and compelling campaign using a three act, nine scene structure. Each act and each scene has a clear narrative purpose of its own and the story has to reach a particular point by the end of each act in order for it to make sense. This is of course a railroad system of adventure writing and GMing, something that unfairly gets a bad name, because it allegedly restricts player choice and autonomy. Part of the point of this series is to speak up for railroad adventures and even to suggest that we find a better name for them.

Act Two

In the previous post we created a first act. The PCs investigated mysterious goings on in the borderlands from the town of Thangard, where Eldritch horrors have been seen escaping from a nearby dimensional portal. They discovered an old enemy, Zarik, was opening portals to find his miss daughter in another dimension but had fallen under the control of a demon entity and have now crossed into the dark dimension.

The point of Act Two

Act two has several jobs to fulfil:

  • It must answer some, if not all of the questions raised by Act One. Who is the demon lord? Where do they hang out? what is motivating them? These are but a few of the questions players might ask. Take the time to ensure that you address these questions because a campaign that doesn’t will lack depth.

(Pro tip: you don’t need to give the PCs chapter and verse on everything in the campaign, you can tell them aspects of information and allude to further information that will be revealed at a later point).

  • It must raise the stakes from act one, we know that demons are spilling out into the world and the PCs must act like heroes to deal with this already quite big problem. What if this dimensional rift is a comparatively small one, but the demon lord has plans to make it much bigger? What if creatures from a third dimension are aware of this and see the opening of the rift as a chance to settle old scores with the demon lord? Maybe the borderlands will become the battlefield upon which this conflict will be fought? The second act is where the PCs discover this and realise what is at stake. It might be interesting to raise the personal stakes and have a family member or loved one of the players' that is threatened, or tie the very survival of the players to the outcome of the mission.

  • It must create the seeds of Act Three, where the PCs will face their endgame with either Zarik or the demon (or both).


In the second act, you might want to create a string of linear tasks, battles and puzzles for the PCs to solve, or this might be the opportunity to create a sandbox section to the adventure. In this you can create a number of locations for them to explore in any order they might wish (preferably with a map) and to interact with the characters and creatures they discover there. Because for the kind of adventure we're envisioning here there needs to be pace and direction, the DM can seed the sandbox with cues to guide the PCs towards the next phase of the adventure, but leave the exploration and the pace to them. Let's create half a dozen locations in the dark dimension of the demon lord.

The PCs find they step into the dimension on to rocky cliffs that look out over a dark and storm tossed sea, lightning quakes overhead and the light illuminates a series of small islands in the dark sea. This is going to be our sandbox, and the PCs will find at the foot of the cliff a small settlement where humanoid wretches who are servants of the demon live, it has a tavern and a sail boat. The nature of the islands and the village need to be determined by what the PCs are looking for. Because they are close to the portal, each island might be a staging post for the demon’s army, which will be coming pretty soon (sharp eyed PCs might see a mighty fleet on the horizon, a day’s sailing away - injecting a sense of urgency is always a good thing).

The PCs need to find how to shut the portal, where Zarik’s daughter is and of course how to kill the demon lord who they will inevitably encounter.

  • The abandoned monastery island: Evil cenobite monks have used the nearest island as a monastery, where they go away and contemplate evil thoughts and think about what their master will do to them if they displease him. This island could be a tomb for undead evil cenobite monks, killed by the demon lord. The PCs might find out that something crucial about the demon lord here, i.e. that he has a weakness that the monks discovered and in a fit of rage he killed them. Monks have an annoying habit of writing things down though, and in the library it might explain the weakness, but the PCs will have to fight their way through the undead monks first. Libraries are also great places to create later reveals for future campaigns. The PCs might find a book that shows a major religion or organisation in their own world is secretly in the service of the demon.

  • The bored garrison island: The Demon Lord hasn’t bothered with this end of his realm for centuries and the one military outpost in the area is garrisoned with bored, mutinous minions, many of which might be rogue humans trapped here for all time. The PCs might be able to pass themselves off as servants of the dark lord and do some exploring and role playing here. Remember that they are not sailing to the islands in a particular order, so they might not have a crucial piece of information from another island. You can always use NPCs to give them information about where something useful, interesting or relevant might be. This island is where the ships will dock and a huge steel causeway will rise from the sea so the infernal army can march to the mainland and pass through the doorway. PCs might need to find a way to destroy the machinery that enables this. There is only so much they can do without blowing their cover though.

  • The home of the scary beast island: Every demonic garrison keeps a few scary beasts chained to a scary beast island. Here is where Zarik’s daughter is kept. Why is she so important to the demon lord? Well not only is she valuable leverage on Zarik, but also, Zarik never realised her mother was also a demon and one of the demon lord’s daughters. The daughter, who now dislikes her father immensely, has realised that she is powerful and wants to stay by her grandfather’s side. The PCs might have to battle and even kill her. Perhaps there is a way of making this Zarik’s problem?

  • The additional quest to save people island: Perhaps through no fault of their own, local peasants from the borderlands have been dragged through the dimension and are kept as prisoners before they are to be sold as slaves in the dark dimension. This might be an opportunity to bust them out, steal a boat and get back to the dimensional doorway?

  • Hermit’s rock: Here an ancient demonic sage sits in a hut on a tiny rock in the sea, contemplating the universe and becoming ever more evil, as evil hermits are wont to do. This is the sort of encounter that can be played lots of different ways. The PCs might discover a Gollum like creature who can be interacted with, negotiated with but never fully trusted. They might find an entity that has been exiled to the rock for millennia or one that transcends time and has meditated its consciousness across the multiverse. It might have information for the PCs that pertains to a later campaign have have seen or travelled from the future. It might be like a Sith lord and looking for a dark apprentice from the ranks of the PCs or any NPCs that are with them. It might have the key to defeating the demon lord that the PCs discovered in the monastery library, such as a dark jewel secreted in its head that the demon lord put there for safekeeping.

Ok, so as you can see the sandbox middle bit is almost a collision of concepts, where the ideas which were generated by the previous act come to fruition and new concepts crash into them. In the previous blog post I mentioned that in each act there were three scenes, and so we need one last scene to finish things off. Currently we have:

Act Two Scene One: Clifftop and demon village.

Act Two Scene Two: Demon island hopping.

Act Two Scene Three: ?

Perhaps scene three is determined by the evil armada that is crashing through the waves? A battle needs to be fought when the fastest lead ship arrives ahead of the troop carriers and one of the Demon Lord’s commanders arrives, aware that mortals have been skulking around the Demon Lord’s islands. In the third scene PCs might also learn that a crucial item for opening and closing the doorway is onboard, which they must steal before crossing back into the Mortal Realm.


So by allowing the middle section to have a function (build on the tension, build the stakes, give the PCs the ability to find the things they will need just as all hope appears to be lost), it is possible to create a balance between sandbox player autonomy and the pace and structure of the adventure. Players will want to explore an interesting place, but there are overall goals to achieve and conundrums to resolve.

In next week’s installment, I’ll detail how we round a campaign like this with epic drama and excitement by looking at Act Three of the campaign, and we’ll also discuss where you take the party from there.

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