When Qin Qi was young, he broke the soul lamp (using demon souls as fuel. The old head of the Qin family once caught a ten-million-year-old demon as fuel. The magic weapon's power was greatly increased.) The demon soul inside passed through his body.
When it was discovered that Qin Qi had corrupted people into humans and ghosts into ghosts. In order to preserve his magic power, the head of the Qin family consulted ancient books and found an ancient technique. The demon soul in Qin Qi's body was taken out and divided into two bodies "yin and yang" in a container. Qin Qi's blood-writing talisman uses the power of "yin" to match the woman's birth date.
It happened that the daughter of the general, Li Wei, and Qin Qi's birth dates coincided with each other. Li Wei had a high fever at that time, and the head of the Qin family used this "yin" to heal himself. A marriage contract was also made for the two of them.
When Li Zhang discovered the container "Soul Pearl", Qin Qi was seriously injured by the demon at that time, triggering the connection between "Yin and Yang".
Qin Qi knew about Li Wei's existence very early. Only once the "yin body" dies, the yang body will not suffer the pain of flesh and blood for the remaining two days of each month.
Although Li Zhang does not have to endure this pain, using the soul beads will backfire and requires the blood of the "yang body" host.
"Yin and Yang" are mutually beneficial and cannot harm each other. One party is in danger, and the other party will be controlled if they don't save it.
Purpose: Catching monsters