Xu Yi did not need to pay much attention to sense it. The spiritual energy here was so abundant it was almost unbelievable.
It was like countless dense threads of spiritual energy. One breath was enough to send them pouring straight into his belly, as if he had taken a drink of Spirit Wine.
Xu Yi's eyes widened. He finally understood why even mid-grade Spirit Stones had been worthless just moments ago.
The spiritual energy he had just inhaled was far denser than what a mid-grade Spirit Stone contained.
In a place where rich spiritual energy was everywhere, it was only natural that low-grade Spirit Stones would be worthless.
Suddenly, another question occurred to him. Staring at Azure Pine Master, he asked, "Then what do people use to trade here?"
"Pills," Azure Pine Master replied. "More precisely, cultivators below the Tribulation stage use Core Pills. They're a kind of pill with remarkable body-tempering effects. Once cultivators reach the Spirit Nurturing Great Perfection stage, ordinary body-tempering techniques are basically useless, and they take too long. That's when Core Pills are needed."
"Because the demand is so widespread, Core Pills naturally became the universal medium of exchange, much like money in the mortal world."
Just then, Xu Yi's expression changed abruptly. "Old Cang, what's going on? After I inhaled that spiritual energy, the Core Essence inside me changed. It seems like the spiritual energy is being stored in there."
"There's nothing strange about it," Azure Pine Master said calmly. "The Tainted Realm and the Four Continents are worlds apart. In fact, the changes in your Qi Sea right now indirectly explain why cultivation realms are divided differently in different worlds."
"The spiritual energy you just inhaled was stored, while your Core Essence disappeared. That proves the so-called Core Essence you had wasn't