Book of Fiends, Volume Two: Armies of the Abyss is a 2002 tabletop game supplement published by Green Ronin Publishing.
Book of Fiends, Volume Two: Armies of the Abyss is a supplement in which a demon‑focused sourcebook details dozens of fiends and their princes, introduces the demon‑bound thaumaturge class, and provides extensive lore, spells, and tools for bringing the chaotic horrors of the Abyss into a campaign.