Io

Io
Aliases	Asgorath, Asragoth, the Concordant Dragon, Creator of Dragonkind, the Great Eternal Wheel, the Ninefold Dragon, Swallower of Shades, the World Shaper
Alignment	All Alignments (Treated as True Neutral)
Divine Rank	Primordial, Intermediate Deity, Dead God
Pantheon	Core, Draconic, Faerûn
Portfolio	Dragons, Primordials
Domains	Dragon, Knowledge, Magic, Spell, Strength, Travel, Wealth
Home Plane	Outlands
Worshippers	Dragons, Dragonborn
Favoured Weapon	Claw, Scimitar

Io as depicted in 4th edition. You can almost see the resemblance to his kids if you squint.

Io (occasionally known as Asgorath or Asgaroth) is the Overdeity of the Dragon Pantheon. An inscrutable entity of seemingly-conflicting motivations, known for doing either very little or a whole lot depending on the incarnation. His most notable feature is that his alignment is, depending on edition, either hotly debated amongst dragon scholars or else conclusively known to be "All of the above."

Not to be confused with "Ao" (or maybe the non-dragon centric version of the same being) who is the Neutral Overdeity of the Forgotten Realms Pantheon, who is also an inscrutable entity known for doing very little.

Not to be confused with the volcanic Galilean Moon of Jupiter.

Core History

Io is one of those gods who has been around since the dawning of existence, worshipped as the creator of dragon kind and the top of the draconic Pantheon.

Pre-4e

Io was introduced in the 2e Council of Wyrms adventure module as the Chief deity of the dragon pantheon and the father of Tiamat and Bahamut. He's also described in the Dragon section of the 2e Monster Mythology splatbook. This entry not only describes him as having all Alignments present in him simultaneously, but also makes him sound like the single most fucking powerful entity in the entire D&D Metasetting. Of note is the fact that as opposed to how things are in 4e, Io remains quite alive and healthy, having fathered Tiamat and Bahamut in the more conventional way (who their mother is, if there is one, is not stated).

4e

During the early conflicts of the gods against their primordial opponents, Io foolishly thought to go wading into battle alone against the Erek-Hus: King of Terror and was cut in two. One half became Bahamut and the other half became Tiamat, while all of the shed blood grew into the Dragonborn race. Coming to realise they were stronger as a team the new creations were able to dispatch their opponent before turning on each other in the feud that remains ever since.

Even though Io was clearly killed and divided into smaller chunks in that engagement, Io is the patron of the Draconic Pantheon in perpetuity, and could not be written off as "Dead" and continues to still grant spells and prayers to its clerics. It is likely that the other dragon gods are simply emanations of Io rather than being wholly separate entities themselves.

Asgorath

In the Forgotten Realms settings of 2nd and 4th edition, Io is instead known as Asgorath, the World Shaper and is only referred to as "Io" by the Dragonborn race. (Io and Dragonborn get practically no mention in 3rd edition Forgotten Realms)

In this incarnation, Asgorath was a primordial entity who contributed to the creation of existence, but for inscrutable reasons was jealous of the worlds that were created. During the Days of Thunder: a war between the Primordials and the Divine beings known as Gods, Asgorath was unleashed to fight against Annam and the Giant deities. Asgorath instead chose to fling a moon at the planet; the smaller fragments of rock transformed into dragon eggs, giving birth to the Dragon race, while the larger chunk nearly destroyed the planet itself.

It was only by the intervention of Ao that the world of Abeir-Toril was saved, by splitting it into the worlds of Abeir & Toril and dividing it equally between the Primordials and the Gods.

Worshipers

Io is primarily worshiped by Dragons and Dragonborn, though the cult is particularly small. Mostly because no-one actually knows what motivates Io to do anything.

Supposedly, True Dragons feel the will of Io in their consciousness from time to time, so even though Io does not actually do much, all dragons agree that Io exists. But when you get dragons together they cannot agree on what alignment Io actually takes, with each race of dragons feeling absolutely certain that Io shares their alignment and represents the epitome of "Draconic behaviour".

It is little wonder then that Dragons get turned off by organized religion when their primary god cant even be consistent. Amongst other races, particularly Dragonborn, worship of Io can find a bit more purchase, though his cult still pales in comparison to that of Bahamut and Tiamat who at least are far more consistent and have goals that have broader appeal.

Anyone who views dragons with awe or wishes to imitate them can turn to Io for guidance. Similarly, as a god of "Balance" and acceptance of manifold alignments, Io makes a good choice for anyone of the Stupid Neutral school of ethics.

DMs who want Io to have some semblance of consistency without using doublethink are advised to look up the "Blind men and the elephant" fable.