Tiamat

Tiamat in Legends has a whole bunch of titles, including but not limited to She was born very soon after the creation of the universe. Visually, she looks identical to the 5 headed one usually depicted in D&D, but she is immensely huge (close to planet-sized).
 * Avater of Dragons
 * Broodmother
 * Godqueen

Notably, she is the only Avatar that has any sense of individuallity. She has effectively become an actual person. She doesn't much care for anything that is not a dragon; her first and foremost concern is that of dragonkind. However, she does not care if a dragon is killed since actual dragons shouldn't be able to be killed.

The platinum dragons are her guardians. As with all Avatars, she is near invulnerable until all of her guard have been killed. List of the platinum dragons, in no particular order:
 * Atarax, Sky Fortress
 * Athezin, Blade of Guile
 * Trenkinol
 * Denzebuth, Eyes of Sin
 * Inawa
 * Scrinethar
 * Xabernare
 * Alonash
 * Rindoayn

She has many children, but the most notable for this campaign is Jessandara (Jesse), who is currently married to Aman.