Ashes of Devotion [ATLA Fanfic]

Lin remembers another life, another war, another world. This condition makes her the perfect soldier for her new life. Reborn in fire and steel, she serves the Fire Nation with unyielding loyalty. When assigned to mentor the young princess Azula, she becomes the only flame Azula cannot master. And somewhere between admiration, rivalry and care, between ashes and fire, lies a hunger that could consume them both. Setting starts in 96, almost four years before the avatar comes back.