The game is set in Io's Blood Isles, a massive archipelago of over sixty great islands with an environmental range spanning from arctic to volcano-riddled tropical islands in a sea heated to boiling by underwater geothermal vents.
According to draconic legend, the dragon creator god, Io, created the archipelago by shedding his blood in grief when he looked upon this unnamed mortal world and found his children engaged in bitter war with each other rather than ruling over the other races as supreme leaders. Whilst the visions Io subsequently sent to his priests compelled the dragons to migrate to the islands, they remained at war, and Io finally forced them to make peace by walking in disguise amongst the humans of the lands beyond the archipelago and shaping them into a warlike theocracy, with dragon-slaying enshrined as a holy tenet. With their numbers and tactics giving them the edge against the individually more powerful but scattered and disunified dragons, humanity seemed on the verge of wiping them out. Now at last was Io able to coax his children to unite and stand together; once they had destroyed the crusaders and driven them from the islands, Io finally coaxed them to abandon their pointless war for supremacy by founding the titular Council of Wyrms, a conclave of the archipelago's most ancient and powerful dragons, who would preserve peace between the draconic clans.
With its focus on playing dragons (alongside the traditional demihumans of elves, dwarves and gnomes, and the newly introduced half-dragons), the setting was a cult hit among fans of D&D, and saw an Updated Re Release in the form of Campaign Option: Council of Wyrms Setting (pictured right), which added playable rules for the Gem Dragon races and the Dragon-Psionicist class/kit. However, the setting has never been officially updated by Wizards of the Coast, and thus it remains an Advanced Dungeons & Dragons 2nd edition exclusive setting.
This setting includes examples of:
- Draconic Humanoid: This was the birthplace of the Half-Dragon as a racial archetype and a player character option.
- Duels Decide Everything: All formal disputes are resolved by undertaking the Challenge of Claw and Wings; a duel in which the quarreling dragons must remain airborn throughout and may only use their innate physical weapons to fight
- Early-Installment Weirdness: Half-dragons debuted in this campaign setting, but are quite removed from the version that would become mainstream in the third edition of Dungeons & Dragons:
- All half-dragons are Nonhuman Humanoid Hybrids — Dragon #206 would later establish that this is a cultural bias, not a biological fact; dragons can procreate with humans, but those of the Io's Blood isles don't want to do so.
- Half-Dragons can only be born to pairings of male dragons and female humanoids. This element would be removed entirely from 3rd edition onwards.
- Only dragon species with a natural ability to shapeshift into humanoid forms can produce half-dragon offspring; dragon-mages using spells to shapeshift can't produce it. This means the only half-dragon lineages native to the Io's Blood Isles are half-golds, half-silvers, and half-bronzes. Dragon #206 subsequently expanded the list as it applied to other worlds: Greyhawk is home to half-golds, half-silvers, and a unique strain; the half-Oerthian Steel Dragon (aka "the Half-Greyhawk Dragon"), but lacks half-bronzes. Dragonlance is only home to a unique strain of half-silvers with human, elven or half-elven "base races". The Forgotten Realms are home to half-golds, half-silvers, half-bronzes, and two unique strains; the half-steel (or "Half-Waterdeep Dragon") and the drow/deep dragon hybrid known as either the half-deep or the drow-dragon. The Realms' subsetting of Kara-tur is different; both species of river dragon, the chiang lung and shen lung, can crossbreed with humanoids, but their offspring are considered an entirely different creature — the River Spirit Folk. Finally, half-iron dragons are called out as a half-dragon species without a specific setting they're tied to. In 3rd edition, any "True" Dragon can freely crossbreed with any species.
- Demihuman-blooded half-dragons replace their demihuman racial powers with draconic ones as they gain levels, whilst human-blooded half-dragons add draconic racial powers as they gain levels. In 3rd edition onwards, being a half-dragon only adds draconic abilities, it doesn't remove any of the original racial abilities.
- Half-dragons have a singular appearance that they all grow to have, regardless of their heritage, which resembles a tall elfin humanoid with skin and hair in shades of their draconic progenitor's scale color, talon-like nails, snakelike eyes, a reptilian cast to the features, and vestigial horns protruding above the temples. They also begin life looking like normal specimens of their non-draconic race, but change into this form as they mature. In 3rd edition, half-dragons are a completely randomized blending of draconic and progenitor racial traits, and are visibly hybridized from birth.
- Fantastic Racism: Dragons generally regard all other dragons as inferior, and demihumans as even more inferior. The one thing that unites them is that they hate humans for their long-ago crusade against dragonkind, and the feeling is mutual; whilst there are some humans native to the Io's Blood islands, the degenerate descendants of stranded survivors from the initial crusade, it is official Council policy to cull their numbers, for fear that the fast-breeding humans will reach plague proportions and become a danger.
- Fighter, Mage, Thief: Subverted. For dragon characters, the available classes are "Dragon" (roughly analogous to Fighter) and the multiclassed Dragon-Mage (Wizard), Dragon-Priest (Cleric) and Dragon-Psionicist (Psychic Powers specialist).
- Magic Knight: Many species of dragons, even if they only take the Dragon class, still gain access to a limited array of wizard and/or cleric spells at higher levels.
- Massive Race Selection: Zigzagged. From a technical perspective, there are only five allowed playable races in a Council of Wyrms game; Dragon, Elf, Dwarf, Gnome or Half-Dragon. But there are ten dragon races (red, blue, black, white, green, gold, silver, copper, brass, bronze), which is upgraded to fifteen in the Updated Re Release (adding amethyst, crystal, emerald, sapphire, topaz)), whilst the half-dragon is technically nine races in one, as it works by pairing an elf, dwarf or gnome base-race with one of three draconic lineages.
- Our Dragons Are Different: The game uses the standard Chromatic, Metallic and, as of the Updated Re Release, Gemstone Dragons of Dungeons & Dragons, and these different subraces each have different breath weapons, inherent spells, and other unique special abilities.
- Updated Re Release: The original Council of Wyrms Boxed Set was subsequently replaced with the expanded Campaign Option: Council of Wyrms Setting, which added new content for Gem Dragons.
