Her father had been General Shu of the Fire Lord's Army. He served in the Earth Kingdom, around the "Not-So-Misty" Palms Oasis. She was cousin to Princess Azula, and very tentative friends with Mai and Ty Lee. But, her dearest friend in all the world was the Crown Prince, Zuko.
Zuko had been her confidante, her dearest companion and above all, her beloved cousin. They did everything together.
It was to her that Zuko complained about Azula, talked about Palace life, or mooned over Mai. They were very close, as close as two cousins could possibly be. Zutana and Zuko were inseparable.
Zutana had been promised to the first Crown Prince, Lu Ten, at birth. She loved Lu Ten more than life itself. When her own father was killed in the war, General Iroh became more than just a prospective father-in-law; he became even closer to her than her own father had been. Then, the letter came that Lu Ten had been killed in the war, during Iroh's siege of Ba Sing Se. Zutana was inconsolable. Zuko could do more than watch over her until Iroh returned to the capital. Then, Iroh and Zutana mourned together.
Zutana was there, on the fateful day of Prince Zuko's Agni Kai. She had stood a few people to the left of Iroh. She was horrified when she learned that the Fire Lord was Zuko's challenger. She saw Iroh look away. Her stomach wrenched and twisted when she heard Zuko's agonized scream. She looked at Iron, and their eyes met, then she saw black.
When she awoke, she was told that Zuko had been banished, and that Iroh accompanied him.
This is what finally destroyed the love she had held for her nation. She had lost her father in their stupid war, then she lost Lu Ten, her cousin had been banished by their ruler and his father to search for the ever elusive Avatar, and Iroh, her kind, loving Dragon of the West, had come home in disgrace after he lost Lu Ten at Ba Sing Se, and now he was gone too. Her faith and love in her nation was gone, and now, so was she.
That night, she left the palace, and the Fire Nation, behind.