1) His father gave him that scar. It's not really a secret, but he doesn't like to talk about it, because chances are it's not any of your business.
2) He retroactively views his uncle as his father-figure, and is going through the process of dismissing his attachment to his biological father as that archetype.
3) He plays the tsungi horn. No one must know.
4) He's set innocent villages on fire, taken Katara hostage, intimidated and bullied peasants of the Earth Kingdom and his ex-crew, captured Aang and dragged him out into the tundra, and basically was the Gaang's biggest enemy for most of the time that he knew them.
5) Having friends again is pretty new to him. When he stops to think about it, he's surprised by how little he's stopped to think about it.
6) He's the Fire Lord. You probably didn't know that yet, but he won't be too shy about mentioning it.
7) His sister is insane and in an asylum. He feels bad for her. She has messed up his life a lot and he's used to hating her, so feeling bad for her feels weird and uncomfortable.
no subject
2) He retroactively views his uncle as his father-figure, and is going through the process of dismissing his attachment to his biological father as that archetype.
3) He plays the tsungi horn. No one must know.
4) He's set innocent villages on fire, taken Katara hostage, intimidated and bullied peasants of the Earth Kingdom and his ex-crew, captured Aang and dragged him out into the tundra, and basically was the Gaang's biggest enemy for most of the time that he knew them.
5) Having friends again is pretty new to him. When he stops to think about it, he's surprised by how little he's stopped to think about it.
6) He's the Fire Lord. You probably didn't know that yet, but he won't be too shy about mentioning it.
7) His sister is insane and in an asylum. He feels bad for her. She has messed up his life a lot and he's used to hating her, so feeling bad for her feels weird and uncomfortable.