Elua

Elua was a confidant of Ursa and Ozai's in the Fire Nation.

History
When sending letters to her hometown of Hira'a, Ursa trusted Elua to deliver them safely, stating that she was like family to her. But in reality, Elua was told by Ozai to file the letters away. One specific letter of importance that shared a secret about Ursa and Ozai's son was brought directly to the young prince by Elua for immediate attention.