He didn't bother listening.
"Sokka—Sokka wait, Sokka. Wait! Sokka! Would you just listen—" he turned.
"Katara," he hissed.
"Tell me, Katara," he drew out his sister's name mockingly.
"Why the fuck should I listen? You got Aang, the avatar, the world's only hope—and more importantly, our friend—you got him executed."
Her teeth clenched.
"Sokka," she sobbed, "it wasn't my—"
He cut her off.
"Bullshit!" he snarled, eyes hard.
"It was your fault."
Sokka turned his back after one last burning glare.
She sobbed hysterically, screaming between gulps of air. "You know what? Fuck you, Sokka!"
He sneered, and turned his head slightly. "You," he breathed cheerfully. "you, dear, dear sister of mine, can go fuck Zuko like you did when his men slit Aang's throat."
He managed a weak, forced grin.
"I said I'd always do what's best for the tribe. I have to, don't I? I'm the only man we had left." Katara whimpered.
"Sokka," she sobbed. "please, Sokka…"
"Katara, Katara, Katara," he sang her name mockingly. "You are no sister of mine, you are no woman of our tribe."
"You can't. You can't! Sokka—you can't do this to me! You're my brother!"
His expression soured, and she saw the bitter fury. "But you are no sister of mine. Katara," he paused, speaking through her frantic pleas. "I hereby disown and expel you. You are no longer a member of the southern water tribes. Do not enter our territory again, traitor."