There were only three people who knew who Izumi's mother was: Iroh, Ursa, and Toph. Aang, Katara, Sokka and Suki spend literal years trying to get Zuko to tell them too, but he never did, even though they were worried, mostly Zuko always said he couldn't tell them, and that he didn't want to.

"What could be the reason for him to keep it a secret?" they'd ask themselves and each other all the time. What was it that Zuko was afraid of?

Why did that woman - whoever she was - tell Iroh and Ursa her secret? Didn't she care that her former lover didn't want his family to know? Why did she have to stay in the shadows, and not have any contact with her own daughter? Was it her choice or was she forced to stay away from Izumi? Why did Iroh and Ursa look so uncomfortable whenever the subject came up?

The day Toph told them she had caught Zuko with her, they got even more confused. He had told everyone that they were not together anymore - why did he lie? Why wouldn't Toph tell them everything and why did she act like the whole situation was hilarious?

Eventually, they gave up on ever finding out. They just accepted that their friend had a secret he would not and could not share with them.

Ironically, a few weeks after they had come to that conclusion, the truth came crashing down on them. They were in the Fire Nation, celebrating another year of peace and Izumi's 11th birthday. The young princess was excited to show off her firebending. They told her to go on, expecting a graceful, yet powerful move.

Instead, she created a small, blue flame.

No. It couldn't be. They were wrong, they were sick, they were insane. But they looked so much alike, and Zuko had made sure Izumi not only knew Azula, but also absolutely loved the woman…

But was it really that weird for a niece to look like her aunt? That could help explaining the blue fire, too. And what father wouldn't want his daughter to get along with her relatives? Surely they were wrong…

The shock and guilt on Zuko's face and Azula's proud smile told them otherwise.