Konoha Hospital, top-floor Isolation Zone.
Ling slowly opened his eyes, a barely perceptible trace of exhaustion and gravity flickering through their azure depths. He had just finished another deep senjutsu examination of the seal inside Uchiha Itachi. The fragment of the darkness source, bound within layer upon layer of the Totsuka Blade's power, was like a sleeping venomous snake, silent most of the time. Recently, however, it had begun to exhibit an extremely regular yet subtle "pulse."
This pulse did not strike against the seal. It was more like... a distant response. Each pulse coincided closely with key moments in the movements of Akatsuki members-most likely Sasuke-identified by the Anbu intelligence department. The momentary resonance had been clearest when the Two-Tails' jinchūriki was captured.
"How is he?" Tsunade's voice came from behind him. She had just finished a high-level meeting on border defenses, and lingering fatigue and worry marked her face.
Ling turned and bowed slightly. "The seal itself remains stable. The Totsuka Blade's power is extraordinary. But... the sealed source has some kind of connection with the outside world that transcends distance. The more frequently Sasuke uses his dark power, and the greater the disturbances he causes, the more pronounced the response here becomes."
He reported his observations and analysis in detail. As Tsunade listened, her expression grew increasingly grim.
"So every time that brat Sasuke uses that damned power, his brother could be put at greater risk?" Tsunade rubbed her temples, feeling a headache coming on. "And we can't even be sure whether this connection runs one way or both! If the thing inside Itachi can influence Sasuke too..."
"For now, the response appears to come primarily from outside. Fluctuations in Sasuke's power trigger resonance in the source inside Itachi," Ling analyzed cautiously. "But over time, or once