Dragonkin: Season I--First Blood
In the time before time, when the worlds were still new, the Original Gods gave birth to creation's first set of twins. Tiamat and Bahamut were created as the embodiment of magic; twin dragons--one black, one platinum. These divine siblings grew in size and ability--inseparably close and fiercely protective of one another.
As they developed into ancient dragons, Bahamut took notice of his sister's cunning nature and thirst for power. Tiamat began to grow cold and distant; usually, she and her brother spent equal time with the Original Gods, but as fate should have it, it was Kol Korran who captivated Tiamat's imagination with his grandiose tales of adventure throughout the worlds. Legend tells us of the fall of Kol Korran the God of Communication, Commerce, and Thievery; as Kol Korran's inner tensions with his dark alter-ego Heren grew in potency, Tiamat's cold and distant nature turned more pointed and argumentative; her only moments of softness or tenderness being when her and her twin/lover were mating--for the Original Gods craved mounts as glorious and as powerful as the twins themselves.
Through Bahamut's kindness, Tiamat gave birth to 10 dragons; five of them Chromatic and five of them Metallic. To fulfill the wants of the Original Gods, each of these first dragons were paired with one of the Original gods. During the splitting of the Gods, Tiamat argued relentlessly with her brother, telling him of the weakness and lack of ambition present in the Gods. When the Original Gods split into the Children of Light, and the Children of Darkness, so too did the closeness and heart-bond between Tiamat and Bahamut dissolve. It was at this point that the Great War of the Gods began: Dragon against Dragon, Child of Light against Child of Darkness.