The dragon god Io existed alone in the Elemental Chaos, formed by random fluctuations of elemental energy. He molded the elements to create Tiamat, the chromatic dragon, and the sapped elemental matter became Bahamut, the metallic dragon. To bring life to his creations, he drained himself of energy, infusing Bahamut with light and Tiamat with darkness. Io’s body became lifeless and rigid, and is now a permanent monument in the Celestial Plane.
Bahamut and Tiamat created many other gods, some of which would go on to create the other planes.
After the creation of the planes and all of the gods, Tiamat was dissatisfied with her power. Even though she had great strength and many allies, her greed drove her to betray others for her own gain. She began stealing weapons, armor and other valuables from the other gods, and fighting them whenever they resisted. Tyr was enraged by this injustice and appealed to Bahamut for help. Bahamut and several other gods decided that Tiamat needed to be imprisoned indefinitely, so they captured her and put her in stasis in a celestial prison.
After repeated attempts to free Tiamat by her evil creations, the prison was deemed insufficient protection. Each of Tiamat’s 5 heads were severed and the essence extracted into 5 Dragon Masks. The relics were sent to the Prime Material Plane, farther from the influence of the gods, and were to be guarded by the Order of the Gauntlet — the order of paladins that worship Bahamut.
The only way to resurrect Tiamat is to perform a ritual involving all 5 Dragon Masks, and 5 adult dragons (Red, Blue, Green, Black, and White).
Betrayal of Arturis
Arturis was a celestial warrior created by Tyr, the god of justice, to eternally stand guard at Tiamat’s tomb. Arturis stood watch at the tomb for eons, smiting any attempted intruders to the tomb and earning Tyr’s favor and respect. Tyr was so enamored by his creation that he spent most of his time trying to increase Arturis’s power, neglecting his other responsibilities and relationships.
Leira, the goddess of illusion and Arturis’s partner, eventually went into a jealous rage and formulated a plan to destroy Arturis. She planned to create an illusory shield that does not block any strikes and demonstrate its supposed power in front Tyr, who would give it to Arturis. Leira persuaded Mask, god of thievery, to steal Hephaestus’s imbued hammer to make the performance in front of Tyr more convincing.
She took the shield and hammer to Tyr and transformed to appear as Hephaestus, then pretended to strike the shield repeatedly with his hammer, failing to damage it. Impressed, Tyr immediately gives the shield to Arturis.
Leira attacked Arturis at Tiamat’s tomb and on the first strike of the battle, Leira’s halberd goes straight though the shield, mortally wounding him. To further punish Tyr, she resurrects him as a demon and banishes him to the prime material plane with a fraction of his power so Tyr has to see his once powerful creation in a weak, corrupted state.