The Gui Xu Profound Darkness Inner Breath Circulation had originally been developed for cultivators fighting in shallow waters. It was a method suited to deep water, so Nascent Soul Real Persons naturally wouldn't need much time to learn it.
The deeper one dived with this water-escape technique, the faster one swam. So Li Fan and the others went straight into the sea, using the cover of night to race along the seabed like barracudas. With the talismans Chen Fushi had given them, they silently evaded the detection of the Xuan Sect and Immortal Palace cultivators above Yanzhou Island.
Having calculated where the formation was, the five of them easily followed the ley lines to the spirit cave where the sword furnace was located.
The seabed here was unexpectedly littered with reefs and rocky outcroppings, making the terrain extremely complex. Within the forest of reefs lay a vast graveyard of shipwrecks. Merchant ships and sea vessels of every kind were scattered about—some broken apart on the seabed, others pierced through by hidden reefs. Human bones were visible here and there, and schools of sharks periodically darted among the wrecks.
Beneath one sunken ship, Liu Zhens found a corner of the formation. He sent a voice transmission. "That's right. The wreck hiding the pill furnace is nearby."
Du Gongshi searched some of the surrounding wrecks and returned with a roll of animal hide. When he shook it open, they found volcanic marrow inside, radiating Crimson Fiend spiritual energy. "They wrapped the fuel stones needed for the sword furnace in fire-beast hide and smuggled them off the island as merchant cargo."
The Real Persons gathered to discuss their next move. "We haven't seen any treasure light appear, so it seems the Divine Transformation demon hasn't moved the sword furnace yet."
"He's lying in