Yin Wujiu and his wife were still present because Shi Wushuang had given her parents a rare life-prolonging item that could be called a divine item at her "peak" times!
The item was called Concentric Living Wood.
It required the husband and wife to nurture it with their magical power for 30 years before it could take effect.
As long as the couple remained in love, no matter what kind of predicament they faced, they didn't complain at all. After that, this extraordinary item could extend one's life by 600 years!
From an investment point of view, it was a huge profit.
However, from the perspective of an immortal cultivator… It was no different from a weak item.
In the cultivation world, couples who were able to remain loving and never complain were usually people with extremely high status, who were born into great families, and whose cultivation bases weren't low!
Otherwise, it would be useless if ordinary cultivators obtained it.