D&D Debrief: “The Sunless Citadel” Session

[While I’m not sure I will have enough content to make this a regularly occurring thing, I have been dungeon mastering a few sessions over the last couple months and, as I prepare for a new one in a few days, thought it might be worth discussing my thinking and using this space as an open archive of my DM notes.]

Previously to reading through it first in Tales of the Yawning Portal, I had never heard of “The Sunless Citadel” module. Published in 2000 as part of an adventure of the same name by Bruce Cordell, it echoed ideas I had seen in other places, however. I was immediately reminded, in fact, of Mass Effect’s (2007) Feros: The Thorian mission where a creature had taken control of the colonists and the player must fight off both the thralls and the creature itself, handling immediate physical threats and a larger, looming mental threat at the same time. (Yogscast’s High Rollers also ran a variant of it for their first episode.)


While the group I have played with has changed members session to session, we usually run about two hours. Added to that challenge are new people and different characters across sessions, too. Whatever the story would be, then, it couldn’t be overly character-based, as the players haven’t had time to explore their characters, and it also couldn’t be too role-playing heavy, either, as that would put the brand-new players at a disadvantage.

Having not previously played with people I knew were going to be in the session, I also decided that a variety of options for encounters would be a good idea. While I wanted a major “boss” fight at the end, I also wanted the ability of the party to use non-combat options to get through most situations as a way to review how different skills worked early-on to build up a way to test various things and explore creative ways to solve problems.


  • Two hours
  • Context or mission-based
  • Low-to-medium role-playing
  • An intermix of combat and non-combat elements
  • An end “boss battle”

Story Elements

One of the ideas that I liked the most from “The Sunless Citadel” was the character of Belak the Outcast. Usually portrayed as being controlled by the Gulthias Tree, the “twisted Druid” as his description goes, is someone who wants to help nature, as with his role, but has been re-directed to help this possessed tree. It makes for a strong premise, like with the Paladin who can also be found with the tree, of classes thought-of as “good” being a source of evil in the world. It also, and a major spoiler, can make the ending more meaningful in having the party learn that killing the tree also kills anything the tree has infected.

Liking what I had seen Matt Mercer do with skill-based games in Critical Roll’s episode 66 (the rules are posted here), I decided that the players would start during a festival and run into Belak there. As they made their way through the festival, various things could happen.

Arm Wrestling: 1d6 + 1d20 versus player’s strength check.

Ring Toss: Insight, Performance, or Slight of Hand check. DC of 14

Pub Crawls: DC 10 Constitution check. +3 per drink. Two fails and the player is unconscious for eight hours.

The last major thing I wanted was for the Gulthias Tree to have a very large amount of health (set to 500), but for the death of each Twig Blight to reduce this by 100. While the presence of Belak at the final battle would be based on the player’s choices, I knew I wanted a ‘clone’ (like with Mass Effect’s (2007) Thorian fight) to be there regardless.


While I initially thought I would have the apples/fruits, if the player ate any, to be something that would overly harm them, this turned out to be something where, with one player who will try to push at any rules I make, that would have led to a major problem. I scaled it back to only 1D4 damage or health depending on the color. (In the original version, players can die from the fruit, and I thought that was rather extreme for level-one characters.)

Something I need to get better at addressing is scaling up the battles to give the players a sense of escalation. During the session, right after the goblin fight, we needed to take a quick break and that led to letting the players take a long rest before the final battle. It helped them get back health and spells, of course, but also made the longer exploration into the cave far less dangerous.

Original Notes

The adventure starts in the village of Oakhurst during the Festival of Twilight, the day-long festival celebrating the end of the harvest and the marking of the Winter solstice. As the party makes their way through the festival, they see contests of skill (arm wrestling, ring toss, and pub crawls). However, this year, a new entry has found their way into the festival.

Arm Wrestling: Roll a d6. That will be the bonus to a d20. Player rolls a strength check.

Ring Toss: Insight, Performance, or Slight of Hand check. DC of 14

Pub Crawls: Constitution check of 10. +3 per drink. Two fails and the player is unconscious for eight hours.

(Garon, barkeep of the local Ol’ Boar Inn, is running a special on drinks — ask inside!)

An outsider by the name of Belak has come to sell some mysterious fruit. Displayed on two rows, the fruit is either perfect, rudy-red apple or, on a second row, albino apples. Belak will attempt to sell the apples to the players for 10 gp per apple. After they buy some, he explains that the red apples grant health while the albino ones take it away. (In each case, 1d4 health points.)

With some questioning, Belak can be convinced to reveal that he has come across what he thinks is the fabled “Sunless Citadel,” an ancient dragon cult fortress that was said to have disappeared during the eruption of Mount Hotenow 150 years ago. He says it is a two-day travel into the mountains and can be located through a cave system.

(If the party does not convince Belak, they can attempt to follow him the next morning when he leaves the town.)

A DC Perception check of >= 15 shows that Belak is covering his arms, hands, and most of his face. He is hiding veins that have a purple, unhealthy tint to them.

If he is charmed, Belak will recommend that the players get rid of the seeds. (If they don’t, and they go to bed, 1d4 Twig Blights will attack them in the morning.)


If the party asks around about the “The Sunless Citadel” (or has a DC 15 History check), they learn that a Paladin of Pelor, Sir Bradford, came through the town two weeks ago and never came back. A Ranger, Karakas, went missing last year around this same time.

During the Journey:

During the night of the first day, the players will be attacked by two Twig Blights. (Anyone will ate from the apples is hurt +2 more by the Twigs.)

Cave Entrance:

The party finds a collection of bones in front of the cave. A careful perception (DC 12) will show that the bones have been arranged and are clearly a warning and not left by animals.

Heading in the cave, the party will find a Goblin Den.

Goblin Den:

Goblins are seemingly guarding the only way deeper into the cave system. (If the party is spying on Belak up to this point, he will speak to the them and they will let him pass.)

The three Goblins will immediately attack the party.

Twilight Grove:

What is left of the “Sunless Citadel” is revealed ahead of the party as a vast opening showing parts of the ramparts and most of the courtyard of an old fortress containing dragon runes. In the center is a monstrous tree (Gulthias Tree) with roots extending down and filling the old hallways.

The room holds four Twig Blights arranged around the tree.

The room contains Balek (if he made it this far) or an illusion of him in twig form. Both them and the Twigs will shake slightly as the party approaches.

A voice will come into the heads of the party. It will say:

“Welcome, Young Ones. Have you also come for a blessing?”

The party must then roll a DC 10 Constitution check. If anyone had eaten any of the apples, they take a -5 to this.

If the party refuses, everyone attacks. However, those under its sway will be Charmed to do nothing until they get pass a DC 10 Constitution check or are healed by another player.

Tree: 500 HP. However, it loses 100 HP per Twig that dies.

If the party kills Balek (if present) or the illusion, they melt into compost. If the tree dies, the spell is broken but the thralls know that they too, because they are infected, will die within 24 hours.