Can I run AD&D's Tomb of Horrors in D&D 5E?

Question

I'm hoping to run a 5th Edition version of the original S1 Tomb of Horrors very soon for my group, as a break from our larger 4E campaign. The problem is, I only have the Basic Rules and the playtest stuff for 5E, and the AD&D ToH module. What adjustments do I need to make to fit it with the new rules? I want to keep things as deadly as the original.

Answer 1

Maintaining the AD&D Feel

If you want to maintain the AD&D feel of this module you have to keep the following in mind: it's a death-trap.

I have played it, I have DMed it and I have spoken to many people who fondly remember the way their characters died in it; I have never spoken to anyone who finished it although I and a few others have escaped from it with some of our party still alive.

I suggest you start by telling your players to roll up their characters and a couple of "spares". This should get their mindset right.

The monsters can be swapped out with their 5th edition equivalents; there are very few of them and they are not the major obstacle anyway (except for Acererak; make sure you read the sidebar on him in the Monster Manual).

The traps and tricks could (should) be played pretty much as written; I would allow the use of Wisdom (Perception) or Intelligence (Insight) to detect them and find out how they work respectively but I would be setting DCs at 25 or 30 - this is a module about player skill, not character skill. See discussion on skill checks below.

It rewards slow methodical play where details matter. Let that be your DM style - tell the players everything (relevant and irrelevant), then tell them again, then again, then ask them what they want to do and require them to be precise. An example of how I'd handle a particular challenge:

Off the first corridor there are a sequence of 10x10 foot rooms which each have a secret door leading to the next (with a twist, of course). As written, each of these opens in a specific way. I would play this with say a DC20 Wisdom (Perception) check to find the doors, with advantage for each room after, say, the second because it is clear that there is one in here somewhere! This should be readily achievable for a party of this level. Finding them doesn't tell you how to open them though; I would allow a DC30 Intelligence (Investigation) to find out how to open them - more or less impossible. So, to open them the players have to state what they are doing - sliding up, sliding left, pushing (where?), pulling (where?) etc.

Skill checks

My preference is to reduce but not eliminate the influence of character skill. This is, if you like, a clarification of the advice given on PHB p.178 (my emphasis).

Finding a Hidden Object

When your character searches for a hidden object such as a secret door or a trap, the DM typically asks you to make a Wisdom (Perception) check. Such a check can be used to find hidden details or other information and clues that you might otherwise overlook.

In most cases, you need to describe where you are looking in order for the DM to determine your chance of success. For example, a key is hidden beneath a set of folded clothes in the top drawer of a bureau. If you tell the DM that you pace around the room, looking at the walls and furniture for clues, you have no chance of finding the key, regardless of your Wisdom (Perception) check result. You would have to specify that you were opening the drawers or searching the bureau in order to have any chance of success.

The "might otherwise overlook" is crucial and can be clarified by adding the following to the example:

If you say you open the drawers and remove the clothes then you find the key regardless of your Wisdom (Perception) check result; indeed the check is not needed at all.

In order to do this you need to set DCs that are very hard (DC25) or impossible (DC30); after all, the place was designed by an evil genius who has refined the place over millennia with the benefit of observing countless test subjects try to break it.

How hard is that?

Well, I have made an anydice program to show this. It assumes:

• the party will help the primary character; giving advantage
• the primary character has a score of 20 in the relevant statistic; giving +5
• the primary character is between 9-12 level; giving +4 proficiency bonus or +8 for expertise

It breaks down like this (rounding to nearest %):

\begin{array}{r|lll} \text{} & \text{DC20} & \text{DC25} & \text{DC30} \\ \hline Non-proficient & \text{51%} & \text{10%} & \text{0%} \\ Proficient & \text{75%} & \text{45%} & \text{0%} \\ Expert & \text{91%} & \text{70%} & \text{36%} \\ with Bardic Inspiration & \text{98%} & \text{85%} & \text{60%} \\ \end{array}

Now there are various spells and magic items that could improve this but if the players do this then they are spending scarce resources and they will be that much weaker latter on.

Thanks to @Mala for inspiring this portion of the answer. Please feel free to point out any errors in my assumptions.

Referring back to the example:

A party with a Bard or Rogue with expertise in the relevant skills will find the doors 91% of the time and work out how to open them without experimentation 36% of the time. I could almost be talked into lowering the DC for detection to 15 which gives a 99.75% chance to find; but then, I'm a soft touch.

Answer 2

Yes you can: it has now been published as a D&D 5e module.

Tomb of Horrors is one of seven modules from previous editions recently released in "Tales From the yawning Portal" published by Wizards of the Coast for use with the D&D 5e system.

All of the monsters (save one, see spoiler) are either in the book, or in the Basic Rules downloadable from Wizards of the Coast: Basic Rules (player), Basic Rules (DM) or the SRD (V5.1).

The only monster missing is the end boss, a demilich, which is listed in the MM but not in the SRD. However, at that point, you can probably adapt a lich from the SRD, if you don't want to buy the MM, since you have the AD&D demilich in front of you. HP are 80 (20d4 maxed).

That said, having the Monster Manual for 5e resolves that one detail.

Answer 3

Chris Perkins adapted Tomb of Horrors for D&D Next in Dungeon magazine, issue 213.

D&D Next was sort of the "beta version" of fifth edition, but it should be very usable.

Answer 4

To convert a module you'll need the AD&D Module and 5e books. Especially the bestiary.

A big part of converting a module from a prior edition to a future edition has to do with the monsters that populate the dungeon, so you'll need your AD&D bestiary, and any monster tables for 5th edition so you can create the encounter tables necessary to run the game in the 5th edition.

Since maps will largely remain unchanged while you're attempting to convert the module over, most of your work will be involved in making sure that the encounters from the AD&D Module and the 5th edition you're creating are similar in difficulty.

Look at the monsters present in the challenges in the AD&D Version of the module, and try to get as close as you can to a similar level challenge in 5th edition while using those monsters found in the module.

Do the same with any traps or non-combat encounters in the dungeon that could cause an issue. Once you've got the encounters down run yourself through a few of the encounters with a group of Pre-generated Player characters to make sure you haven't grossly overestimated or underestimated a parties ability to bypass the challenge.

Once you've done that I'd say you should be in the clear. Its hard work though, I wish you luck!

Answer 5

It's not that difficult to convert from 2>5, in fact I think the feel is easier than 2nd Ed to 3rd or 4th edition, the question is are your players ready for the fact that 2nd Edition unrecoverable player death was much more common. I've played through ToH ~ a dozen times as a player or DM, it was one of the first modules I ever owned (1984?) and I absolutely love the dungeon but it's not for those who have a strong attachment to their characters.

In some respects it's easier in 5th since the game itself is more forgiving/balanced.

As far as the checks are concerned, I'm not too strict but the party may have to take an extraordinary amount of in game time to move to the next location. Shouldn't greatly effect game play but makes it clear how difficult things are. Look at the provided characters in the back of the module as an example...

Favorite ToH quote (15 min into starting the module, brand new character)

I put the itty bitty tip of my pinkie finger into the black orb

Lucky for him he was one of a set of triplets who all somehow managed to become mages...

I think it's time to introduce my kids into the joys of ToH

and fighting a lich with +3 weapons...