3: The Citadel of Thunder was written by David A. Hargrave, with illustrations by Greg Espinoza, and was published by Grimoire Games in 1979 as a 32-page book with two cardstock sheets.

[1] Shannon Appelcline commented that "Following the publication of Caliban, the rest of 1979 was a great year for Grimoire Games.

None of these were ground-breaking — like the Arduin Grimoires were — but they were tough, competitive adventures of the sort more common at the dawn of the industry.

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".