Fang Yuan shook his head and sighed.
The cost of feeding Wisdom Gu was simply too great. Only Lang Ya Earth Spirit had been willing to pay it.
Fang Yuan had gained a new life through the Supreme Immortal Embryo Gu and now appeared to be sixteen years old. The average lifespan of humans in this world was one hundred years. One hundred minus sixteen meant Fang Yuan still had roughly eighty-four years left to live, which counted as quite a long time.
But even so, Fang Yuan reckoned that if he obtained lifespan Gu, he would basically use it on himself. Even if he did not use it now, he would still hoard it for a rainy day.
Lifespan Gu was merely a mortal Gu.
Yet among Gu Immortal transactions, lifespan Gu was the most powerful hard currency. Almost nothing could compare to it.
There were two greatest hurdles in Gu Immortal cultivation: one was tribulations, and the other was lifespan.
Even Immortal Venerables and Demon Venerables had to endure the constraints of these two hurdles.
In fact, when Ju Yang Immortal Venerable had set up Eighty-Eight True Yang Building, one of his most important purposes had been to scour the entirety of Northern Plains for lifespan Gu and extend his life. Feeding Wisdom Gu had been a secondary concern. During Ju Yang Immortal Venerable's later years, Wisdom Gu had remained hungry for a long period of time, forced into deep slumber and unable to be used.
Later, You Hun Demon Venerable explored Eighty-Eight True Yang Building and discovered the Wisdom Gu within as well. Unfortunately, he could neither use nor afford to feed it. Lifespan Gu was difficult to find, and he did not even have enough for himself. However, with his soul path attainment, he had long