Dragonborn of Bahamut

The Dragonborn of Bahamut (Ux Bahamuti, in Draconic) were a race of dragonkind created by the deity Bahamut during the Time of Dragons. They were creatures reborn from good-aligned humanoids who, to show their devotion to Bahamut, willingly took on draconic traits in place of their original biology. They were the antithesis of the spawn of Tiamat.

The Rite of Rebirth
Rarely, members of the humanoid, non-draconic races heard the call of Bahamut, asking them if they wanted to devote themselves completely to Bahamut. Normally it was first heard before adolescence, but sometimes adults heard it as well. Not all those who were called answered, but those who did it underwent the Rite of Rebirth. Those who committed to this demanding ritual meditated for a full day and night, their head filled with reminders of all they were giving up.

Those who elected to go on, prepared an specially builded egg-shaped chamber and entered on it to sleep for 24 hours, emerging as an adult dragonborn (regardless of his or her previous age), a draconic humanoid with metallic scales and draconic abilities. They had reborn as permanent champions against Tiamat and her spawn.

Traits
Bahamut gave his adoptive sons the best traits of the Metallic Dragons, but not all dragonborn were born with the same abilities. Some were born with the aspect of Heart, and those dragonborn developed the ability to use a dragon breath; other were born with the aspect of Wings, which gave them draconic wings and the ability to fly; and other were blessed with the aspect of Mind, which sharpened their senses and gave them the immunity to sleep and paralysis effects. All dragonborn were also immune to the frightful presence of dragons and had an innate sense of how to defend themselves of attacks from dragons.

For all the blessings they received, however, those who chose to become dragonborn payed a high cost: they became sterile, thought Bahamut had a reason for this. He wanted to impart this blessing only to those who accepted his calling on their own free will, without tying someone who didn't wanted to be a champion of Bahamut because of the conditions of their birth.

Like other draconic creatures, Dragonborn of Bahamut were long-lived. The oldest of them lived up to 600 years. Due to their crusade against the forces of Tiamat, however, most of them died young.

Personality
The dragonborn of Bahamut were honorable beings, and carried themselves with good deportment acting as the honorable emissaries of their adoptive father. Due to the sacrifice they had made, dragonborn had a strong sense of identity with a clear purpose of one with stringent principles. The war against Tiamat encompassed all in the dragonborn lives. Everything they did only furthered this commitment, even if didn't had immediate effects.

Tarnished Dragonborn
Bahamut did not tolerate evil, and his children were not an exception. The Platinum Dragon turned a forgiving eye towards some slightly immoral methods used against Tiamat and her servants, but he didn't condone any form of evil behavior on the part of his children. Bahamut send his aspects to warn those who committed repeated evil acts, and if they were penitent the aspect gave them a quest to redeem themselves. But if evil dragonborn refused to atone for their sins, Bahamut reclaimed back his blessings and the tarnished dragonborn were reverted back to their original race and form.

History
The Parwiccan Cycle tell of dragonborn knights that existed long ago, in the long-forgotten Time of Dragons, loyal warriors of the Platinum Dragon in the Dragonfall War. However, they vanished from Faerûn and only reappeared again in 1373 DR, when humanoids loyal to Bahamut underwent the Rite of Rebirth to help to stop the magic of the Dracorage mythal. With the help of the Sisterhood of Essembra, some communities of Dragonborn of Bahamut were created in the woods near Essembra.

The Platinum Cadre of Tymanther had the theory that the abeiran dragonborns weren't the creations of the dragons of Abeir, but instead the ancient creations of the Platinum Dragon, and some older dragons knew that the two races of dragonborn were in fact related.