Deep underground, all was silent. Only a low hum echoed through layer upon layer of rock, as though some sleeping beast in the earth's depths had turned over.
The sound did not come from any single direction. It was everywhere, seeping through the crimson, vein-like lightning channels and into the marrow of everyone who set foot here.
Xuan and his group of four stood atop iron sand controlled by Baba Tesshin, floating half a meter above the ground like ghosts as they glided forward in complete silence.
Under the precise control of magnetism, the iron sand created no friction against the ground. It was the most perfect method of stealth they could devise.
Along the way, Xuan's fingers occasionally brushed lightly over the rock walls. One imperceptible interference node after another was silently planted into the energy fields of the lightning channels, forming a fluid shielding network that constantly recalibrated itself in an attempt to confuse Kumogakure's surveillance system.
Yet as they ventured deeper, the intangible pressure grew increasingly oppressive.
The passage ahead suddenly opened up into a vast cavern large enough for more than a dozen people to stand side by side.
At the end of the cavern was not an exit, but an enormous rock wall that had been artificially flattened and polished smooth as a mirror.
Embedded in the very center of the wall was a colossal bronze eyeball over ten meters in diameter.
Its construction was exquisitely intricate. Ancient bronze was engraved with complex lightning patterns, but the most terrifying part was its pupil—it was not made of any physical substance, but a spherical mass of lightning flowing at high speed and constantly changing shape.
The lightning pupil slowly rotated. Every sweep it made carried chakra fluctuations that made one's soul tremble.
"The Lightning Heart Eye..."