The 100-Room Citadel: A Replayable 5e Megadungeon for Small Groups

The 100-Room Citadel is a replayable 5e megadungeon built for the tables everyone else forgets: the two- and three-player groups who still want the sprawl of a real dungeon crawl. Most megadungeons assume a full party of four to six and weeks of preparation. This one is tuned from the very first roll for small groups at low levels, and it runs straight off the page with zero prep. It is also a milestone. The 100-Room Citadel is the 100th book published by Anvil N Ink, and we built it to earn the number. Inside you will find a dice-driven room engine that keeps the dungeon fresh for months, more than a hundred battle maps, thirty-six original monsters with full stat blocks, and four ready-to-play heroes so you can sit down and start tonight. Whether you are a busy Game Master hunting a campaign-length adventure you can run without the prep grind, or a duo that wants a genuinely big D&D 5e dungeon scaled to your table, this is the megadungeon made for you.

A 5e Megadungeon That Reshuffles Every Session

Here is what makes it replayable. At the start of each zone, your party rolls to see which room opens next, so the citadel deals its hundred rooms like a deck of cards. The same book runs a hundred different ways, and the math is not marketing fluff: each zone alone opens in over ninety thousand possible orders. Clear four rooms to wake the zone’s warden. Beat the warden to claim its seal. Collect all four seals and the road to the Cartographer-King finally opens.

The path is never the same twice, but the climb always builds. That structure is what turns a one-and-done module into a 5e megadungeon you return to for months. You are not re-reading a story you already know. You are rolling into a castle that rearranged itself while you were gone, and the tension of not knowing which door opens next is the engine that keeps a small table hooked.

Built for Two or Three Players, Not a Scaled-Down Party

Small groups usually get the short end of published adventures. Encounters are written for four to six heroes, and a duo either bounces off a wall of hit points or gets a hero dropped in a single unlucky round. The 100-Room Citadel fixes that at the design level. Every fight is survivable for two or three characters at levels two and three, and no attack in the book can drop a full-health hero in one blow.

A guaranteed gear track keeps your party in the fight all the way to the throne, so you never stall out under-equipped. There is no leveling to track, no bookkeeping to babysit, and every repeatable hazard is capped so the dungeon cannot grind a short-handed table to dust. It is big-dungeon scope with small-table math, and that is exactly the 5e megadungeon two- and three-player groups have been missing.

One Hundred Rooms Across Five Living Zones

The citadel climbs through five themed zones, each with its own warden boss, its own reward vault, and its own map that never draws the same way twice. You fight up through the Overgrown Approach, where the outer keep has surrendered to briar and root, and down into the Sunken Catacombs, where the dead still keep the King’s old order.

Beyond them wait the Elemental Vaults, where fire, ice, and storm strain behind failing seals, and the Clockwork Works, a hall of hand-wrought brass that winds itself back together as you tear it apart. Finally the Living Towers, where the citadel stops pretending to be a building at all. Every zone raises the threat, and every zone hides a Dungeon Master handout that reveals a little more of what is waiting above.

Each warden is a full boss fight built to close out its zone without cheap kills, and each drops a seal that carries the campaign forward. The Bramble Warden, the Sepulcher Knight, the Tempest Armor, and the Brass Scribe each teach the party something they will need at the summit, so the difficulty curve feels earned rather than arbitrary by the time the Cartographer-King is finally in reach.

The Warden’s Vault Rewards Every Room You Clear

Exploration only matters when it pays, so the 100-Room Citadel runs on a keys-and-chests economy called the Warden’s Vault. Clearing a room earns a key. Keys open the zone’s chests, and the chests hold the consumables, permanents, and one-time saves that keep a small party swinging. Greedy tables that sweep every room are rewarded for it, and cautious tables that rush the wardens still get enough to survive.

It is a simple loop that solves the oldest problem in a dungeon crawl: giving players a real reason to open the door they could have walked past. Paired with the four-warden seal chain that builds to the Cartographer-King, every choice on the map feeds the climb toward two possible endings your table decides for itself.

Every Room Mapped, Nothing Left to Prepare

A 5e megadungeon lives or dies on how fast the Game Master can run it, so every one of the hundred rooms comes with its own top-down battle map and read-aloud text written to run cold. There is nothing to draw before your session and nothing to look up mid-fight. Drop the book on the table, and the map for the room your party just rolled is right there on the page.

That map count is not filler. More than a hundred gridded encounters, a full-citadel reference map, and reproducible player handouts mean this replayable 5e megadungeon arrives table-ready in a way most big dungeons never manage. The prep you would normally sink into a campaign this size is simply already done.

What’s Included

The 100-Room Citadel is a complete, ready-to-run package. Everything you need to run the full campaign is between the covers:

• One hundred fully keyed rooms across five themed zones, each with a warden boss and a reward vault
• A dice-driven room engine that reshuffles the dungeon every session for months of replay
• More than one hundred top-down battle maps, one for every room plus a full-citadel reference map
• Thirty-six original creatures with complete stat blocks, tuned so nothing one-shots a hero
• Four ready-to-play characters with full sheets, plus reproducible player handouts and tracking sheets
• A four-warden seal chain that builds to the Cartographer-King, with two endings your table chooses
• Roughly 326 pages, built for 2-3 players at levels 2-3 across about five sessions of play

Perfect For

Small groups of two or three who want a full dungeon crawl scaled honestly to their table, not a six-player module they have to nerf on the fly.

Busy Game Masters who want a campaign-length 5e adventure with zero prep and near-endless replay from a single book.

Megadungeon fans who love the sprawl of a classic dungeon but need it to actually work for a duo or trio.

Duos and trios hunting a fifth-edition-compatible dungeon they can return to for months without replaying the same rooms.

Collectors and long-time readers who want the milestone: the 100th Anvil N Ink book, and the biggest single adventure we have ever put in one volume.

A Milestone Hundredth Book

Anvil N Ink builds small-group 5e adventures for players with real lives and limited prep time, across every tone from comedy to cosmic horror. The 100-Room Citadel is our hundredth title, and it is deliberately the most ambitious thing on the shelf: a full megadungeon that still respects a two-hour game night and a three-person table. If this is your first book from us, it is a strong place to start. If you have been with us for a while, this is the one we have been building toward.

Roll the Dice and Take the Throne

You do not need a full party, a free weekend, or an evening of prep to run a real dungeon crawl. You need one book, a handful of dice, and a table of two or three. The 100-Room Citadel gives you a replayable 5e megadungeon that opens a different castle every night and keeps your small group climbing for months. Open the gate, roll the dice, and find out which citadel you get tonight. It is available now in paperback, ebook, and DRM-free PDF, and it is the single biggest adventure we have ever handed a small table.

The 100-Room Citadel is the replayable 5e megadungeon that turns two or three players and a single book into a hundred different climbs to the throne.