Creating a D&D DM's Brain Attic with Obsidian

A sprawling pile of D&D sourcebooks and third-party content stops being useful when it turns into a “titles I’ll never read” problem. The fix is a structured Obsidian vault that turns thousands of monster, item, and NPC notes into a searchable, rollable system—so ideas surface exactly when a game needs them.

Instead of keeping D&D notes mixed with everything else, the setup splits content into dedicated folders and then adds navigation pages outside those folders. Monsters live in a markdown file per creature, including SRD entries and a heavy emphasis on third-party monsters—chosen because they tend to be more interesting to run and fight. The key upgrade is tagging: each monster page includes parameters that feed Dataview queries. Dataview turns markdown into a queryable database, letting the DM pull results by name fragments, tags, CR, type, environment, and even the source book plus page reference. A search for “Bullywug” becomes a reusable query, and the same query template can be swapped to find “shape changers” by filtering tags like type and shapechange. The payoff is practical: the results list not only what fits, but also at-a-glance stats (CR, type, environment) and where to find the original text.

Magical items get the same treatment. Items are organized by folder, with SRD material alongside third-party sources such as Vault of Magic. For item generation, the vault includes “Magic Item Tables” that replace WotC tables, including nested tables that instruct how to roll multiple times and then select from dozens of sub-tables based on CR. When a roll lands on a specific entry, each table result links to a markdown page with the item’s full text and variations. When the DM needs something narrower—like an item that targets a player’s Constitution or one that fits a particular spellcaster profile—Dataview queries again filter by item traits and return the matching items with their categories (armor, weapon, wondrous).

NPC creation is handled through both quick and detailed workflows. An NPCs page pulls from prebuilt tables using the Obsidian Dice Roller plugin (Jeremy Valentine), so the DM can roll a throwaway name with a short description and alignment, then optionally roll deeper traits like mannerisms, ideals, and more. For more substantial NPCs, the vault incorporates entries from The Game Masters Book of Random NPCs, including boxed text, perception-based learnable details, class-leaning insights (insightful, roguish, spellcasters), backstory, and even what the NPC carries—so “what’s in their pockets?” questions don’t derail preparation.

Beyond core stat blocks, the vault adds inspiration and reduced planning load. A Corrupted Tarot page uses a deck as an abstract writing prompt, with card-by-card meanings and a “corrupted” interpretation to spark new directions. Another major addition is Sly Flourish’s Uncovered Secrets, volume one, which supplies tables for secrets and clue structures—such as artifact hunts broken into rolls for artifact type, location, environment, guardian, and more. The creator acknowledges the system takes work, but argues it prevents books from going unused by forcing every purchase into a repeatable retrieval and generation pipeline. The approach echoes Mike Shea’s “DM’s Brain Attic” concept, but shifts it from passive reading to an always-on, query-driven brain dump that surfaces ideas at the moment they’re needed.