Tletl-Meztli is known as The Fire Moon, and Desirable Above All Things (Although the last one could just be what Eztli-Tenoch calls her, because of their love.) Slak also calls her "attractive" the first time they meet.
Salea longed to return to the days of old, "Before the first born of blood." long with her husband Sars. They were a King and Queen who "Ascended" to Godhood known as Tletl-Meztli and Eztli-Tenoch.
Their rein saw the ancestors of the Nomad rule much of the world. Their paths parted when Eztli was imprisoned by a seal. Tletl continued to lead the Blood-Mad tribes of Nomad long after their empire fell apart and over time resorted to killing thousands of people in an attempt to find those who had the blood that created thee seal. This did not make them very popular with the Quaid who set about erasing their existence.
Though weakened by the absence of her husband, she was still eternal and unable to die. As a result she "lived many lives" without him and carved her name across the land. Abandoning the Blood Tribes she disappeared, without her they too fell apart. However, they maintained enough position to attack many of the other Nomad tribes, including many of Ketta tribe the Geka.
Over time she began to realize that the world was better off without their God-like powers. Tletl did not have the power to end her own existence and sought out those with the power to break the seal so she could beg her husband for release from their Godly powers and return to being who they were originally. Despite loving her husband, she could never not bring herself to rejoin him and knew their reunion would bring about the end of the world.
In the Game+ sidequest, she enlists the aid of Azra's companions, and then of Azra herself and in an attempt to reason with Eztli summons him. Her words fall on deaf ears and mmakes his own attempts to bring Tletl around to his thinking instead. Eztli comes to believe that Tletl has both betrayed him and deserted her responsibilities as a"God". Finally when she asks for the power of destruction to end their existence, he kills her, releasing her from her God-hood entirely as she requested, but chooses not to go with her. With her death Eztli declares all links to the past are gone.
With her death, the part of her that Azra was linked to via Eztli's power dies and Azra herself feels her passing as a result.