“Thousand Thunder Falls” from the dungeon module The Citadel of Thunder

The Citadel of Thunder (also known as Arduin Dungeon Number Three) was a standalone short story and gaming module written in 1979 by David A. Hargrave and published by Grimoire Games. It was based upon Hargrave’s gaming system known as Arduin. It is the third of only four standalone “dungeon” books created by Hargrave as an extension of his Arduin Multiverse, which at the time of The Howling Tower’s publication was known as The Arduin Trilogy.


At twenty-four pages, The Citadel of Thunder contains overland maps with area descriptions and encounter charts, four dungeon levels with maps and room descriptions, eight pocket sized magic artifact cards and eight illustrated monster cards with statistics. There were also unique new traps in a matrix at the rear of the module.[1]

Illustrations were contributed by Greg Espinoza.


While designed for use with the Arduin gaming system, The Howling Tower is usable with any d20 or other RPG system. It was designed for mid-level characters (levels 5 through 8).


The Citadel of Thunder was originally published by Grimoire Games and went out of print in 1984. In 2002 reprints of The Citadel of Thunder were made available from Emperor’s Choice Games and Miniatures, but were discontinued in August 2006. Since then, the company folded The Citadel of Thunder and all other Arduin dungeon modules into a single publication called “Vaults of the Weaver.”[2]


The module concerned the events at a place in the Arduin multiverse called “Thousand Thunder Falls.” The last priest of the evil god Aeos returned to the Citadel of Thunder, which was hidden inside the protection of a giant Niagra-sized waterfall. He had survived an attack on his order by the forces of good, and returning to the citadel vowed vengeance against all who had risen against he and his kind.

The priest and his remaining kind then spent thirteen years inside the citadel planning and preparing for a retaliation. The time finally came to cast the final rite that would bring ultimate evil from the stars, a Night Demon who would do the priest’s bidding. It was all going to plan until an Elven female spy interrupted the ritual and the Night Demon was gated in, uncontrolled. There was much havoc afterwards. When all was said and done, the Citadel of Thunder remained abandoned and forgotten until…

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