Over the next few days, Ling felt like a test subject left to simmer over a low flame. Far from fading in response to his vigilance, the sense of being watched intensified, seeping into every opening. It was no longer just a fleeting glimpse or a faint sound; it had begun to reach into stranger realms.
Sometimes, while he struggled to maintain a formula model, he would suddenly feel a cold strand of chakra, slick with probing curiosity, brush the edge of his projected energy like a flicking snake's tongue. It left him with the deeply unsettling sensation of having been "tasted," then vanished. Sometimes, late at night, caught between sleep and waking, he seemed to hear low, broken syllables simulated through chakra scraping directly across the surface of his exhausted consciousness, trying to pry open a crack.
He knew Orochimaru was probing him, using every possible means to test the limits of his mental defense and assess the Beacon's response patterns. Every time, he had to force down the unease and terror churning deep within his soul and muster every scrap of willpower. Like a soldier defending the last fortress, he held fast to the gates of his consciousness and kept the Beacon stable. This was more tormenting than Tobirama's straightforward "hammering"-a slow flaying of the mind.
Tobirama remained indifferent. Whenever Ling reported these anomalies, he merely recorded more detailed data and adjusted the intensity of the next round of "interference resistance training," as though Ling had simply delivered a report on a test subject's stress responses.
"He's looking for the 'keyhole.'" During a break in training, Tobirama offered a rare extra explanation. His fingers tapped the air, tracing a few simple trails of light to represent chakra flow. "Every seal, every defense, has a theoretically weakest resonance point.