Azhara

An Astral warrior, one of the great protectors of the sacred city of Adastria.

She was close friends with the sorcerer Flegetonte and researcher Albireo. (They were probably in love with her. Classic love triangle stuff)
She was popular for her strength, optimism, and unyielding desire to protect the people, even those without Astral gifts. People used to joke that her long light blue hair was representative of her deep connection with the skies and the stars.
tldr she died in the pits which was very sad. Her final wishes were to protect the people. (Classic woman dying for character development)
Flegetonte was able to move on after her death and resolved to carry out her last wish. On the other hand, Albireo couldn't get over it and grew obsessed with any possible way of bringing her back, not wanting to ever forget her smile. As such, her death caused the two to drift apart.
The Astral Guardian’s humanoid appearance was modeled after her. As a result, that makes Aria look like her too, though younger.