Summary: Kyuubi warned Sasuke not to kill Naruto. He should have listened.
Our Own Creation
"I told you you'd regret it." Naruto's smooth voice was silk and danger and fire and wrong
Sasuke clenched his teeth, his body controlled into fine tremors. He knew this place, had been here once before. Naruto's mind, never really a happy place, but never this dark.
"Naruto?" he stepped forward cautiously, hand on the hilt of his sword. And then blonde hair blocked his vision, the impossibly fast movement startled him, but Sasuke refused to let it show; he could be just as fast.
Sasuke swung and his hand was caught, the blade shattered seemingly without being touched. Widened eyes turned to his old rival. He felt the bones in his hand creak under the pressure.
"Careful Uchiha." Slitted pupils glared red into his own and he caught the sharp grin. "Here there be monsters".