Demon Idol

A gamist Advanced Dungeons & Dragons interpretation.

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Rules Overview

This page contains general rules for playing Demon Idol AD&D.

Remember, Demon Idol is largely an interpretation of AD&D, because there are many cases where the rules are not precise, or do not provide gameable mechanics. One of the main purposes of Demon Idol is to provide a smooth, coherent, battle-tested interpretation of AD&D. Therefore, we don't call out every time we make an interpretation of the rules, because that would be really messy. We also don't call out whenever we make a stylistic choice (for example, encouraging DMs to roll dice publicly).

However, in any case where Demon Idol adds an explicit extension to a rule (always in the spirit of the game), an Ex will appear. That way, as you play, you can easily delete or replace our extensions for your campaign, knowing that their removal will not break your game or the cohesiveness of the Demon Idol interpretation. Extensions are always marked with that Ex, and are likely to be improved over time if they are new.

Unearthed Arcana

For a list of rules we use from UA, see Unearthed Arcana.

The following are a list of “gotchas” that most players will run into at one point or another. These are rules where there is a direct contradiction in the books that must be resolved.

  • Combat examples in the PHB and DMG: These infamously often contradict the rules and should be ignored.
  • Small and medium shields: See Equipment.
  • Magic armor weight: See Equipment.
  • Lair treasure scaling based on # AP: See Lair.
  • Barding weights are too great and need to be adjusted: See Barding.
  • Demihumans/non-humans such as dwarves and elves are referred to as “humans” in some places in the text, in particular the MM. This appears to be intentional.1)

Rules changes

Demon Idol operates with only two rules changes. Check them out.

Character stables

Players should keep a character stable.

Players can control only one PC at a time unless there are less than 4 players at a session, in which case players may control more than one PC so a total of 4 PCs is reached, as desired by those players. Exceptions beyond this will be made only for unusual in-world campaign circumstances such as PCs rescuing other PCs, and never simply because more power is desired. Use henchmen!


The DM should endeavor to roll dice publicly.Ex

These rolls are typically made privately by the DM, and may happen unannounced: wandering monsters, random encounters, Elven passive concealed door detection, ad-hoc treasure, and reaction (does not include character attempts to communicate). In many cases, players can roll their own move silently and hide in shadows checks. To know when, check out thief abilities.


See MM 97 Troglodyte entry, for example. The bulk of these being in the MM suggests that this is a phenomenon of terminology developing during the early days.
rules_overview.txt · Last modified: 2024-02-20 00:48 by poems