Headstrong as the Blood of the Earth
It was easy, Kuzon said, to bend lava, but his leg was raw and pink under his pants and he was always tired when he came home from his Sifu's trips. Aang could see it breaking him, tearing him to pieces, and whenever he saw Kuzon's scar, he felt it like a heavy punch to the stomach.
But Kuzon was a firebender, and he had a goal.
"I'm not afraid of death," he said, his mouth twisted into a grin too old for his 14-year-old face. "If I was, I couldn't bear moving." Kuzon pressed Aang's hand to his riddled thigh and smiled, because he was a firebender and would only let the earth take him (by its blood or its body, he didn't care). "We are breakable. We will die. Our flesh burns, and heals. What can you do? What can you do?"
Kuzon showed Aang volcanoes and the art of remaining nonchalant and women and why, exactly, lazy days away from home, tipping rhinocows, were so much better than days at work. He showed Aang how to meditate when things weren't calm and how to deal with jerks and drunks. He showed Aang that the body was still a temple, no matter how enlightened the spirit, and that he needn't be a glutton to indulge in its needs and wants. He showed Aang that humans were more precious than anything else, and that nothing in the world had more faults.
And a hundred other things: All the card games he knew, how to blend in when it's wiser than sticking out, how to cry until it hurt and how to laugh until he cried, how to make girls hate him and how to tame wild animals long enough to ride them.
Kuzon limped for a long time, and pretended he wasn't tired. He made Aang watch them bandage his leg the first time, staring at him until Aang could finally look away and find his eyes. "It's pretty sick, isn't it?" he asked, trying to laugh instead of grimace. And later, "You gotta watch out for the earth. It just doesn't realize we're here."
He was too old for his body, marching to his Sifu every morning and back to his Father every night, because he loved his country and his mother and wanted to be in history books.
The monks made Aang feel like he understood the world, but Kuzon made him understand people, and the way they hurt, and the way they flourished (and it wasn't by meditating at sunset, but by laughing at bad jokes until the sunset ended and the stars beckoned them home).
Kuzon was Aang's first kiss and maybe almost his first love, but before all of that, Kuzon was his best friend. Simple as that.