They passed through a long bluestone corridor, and the floor beneath their feet gradually gave way to steps paved entirely with obsidian.
Fist-sized moonlight stones studded the surrounding walls, giving off a soft glow.
The higher they climbed, the richer the medicinal fragrance in the air became.
Elder Han Li walked half a step ahead, slightly bowed, his manner courteous.
The other white-haired elder was Sheng Feng, an Eighth-Grade Low-Level master long renowned in the Pill Tower. He walked beside Lu Heng, treading lightly.
Though both men were centuries old, they had long since cast aside all airs of seniority before Lu Heng, who possessed three Heavenly Flames and a Spirit Realm Soul.
On the Central Plains Continent, strength and alchemical skill were the only measures that mattered.
A short while later, the three stopped before a heavy door forged from a single piece of Ten-Thousand-Year Cold Iron.
Han Li took an intricately engraved Purple-Gold Token from his sleeve and pressed it into a recess at the center of the door.
With a dull clatter of machinery, the heavy door slowly slid inward.
Beyond it lay a spacious stone hall a hundred zhang across.
Three hundred and sixty top-grade Fire Crystals were set into the ceiling, arranged into a vast Spirit Gathering Array.
Dark red lines were carved across the floor, with warm earthcore fire drawn from deep underground faintly flowing through them.
Layers of powerful spatial barriers sealed the entire chamber tight. No disturbance from outside could penetrate it.
This was Saint Dan City's most secure, top-tier assessment venue, reserved for Peak Seventh-Grade alchemists seeking to advance to Eighth-Grade masters.
Han Li stepped aside and gestured for him to enter.
"Master Lu, a saint of the Pill Tower personally laid the Flame-Stabilizing Grand Array here. It can withstand the