Sword of Sword III, what is the story of Xi Feng and Shui Bi in it?

Shui Bi was originally a female general from heaven. When she was sent to capture Fei Peng, she fell in love with the demon Xifeng at first sight and made an appointment to elope. In order to avoid being tracked by the gods, they used their magic power to build a mobile city in the sky. They used the time gap of "seven days in the sky and a thousand years in the world" to constantly move around the world to avoid the punishment of the gods. Because she is a Valkyrie in the divine world, she has profound magical abilities that mortals simply cannot compete with.

Jingtian and other people went from Anxi to Undersea City, and met the wind and green water at the bottom. Xifeng is a general in the demon world and was originally the right-hand man of the demon Zhengzhenglou; Shui Bi was originally a goddess in the god world, with high magical power and known as the "female war goddess". During the many battles between Chonglou and Fei Peng, they all followed behind. As the saying goes, no acquaintance can be achieved without fighting. Shuibi and Xifeng fell in love at first sight and made an appointment to elope. Since Shuibi is a god and has a special mark, it is easy for people in the divine world to find her. Xi Feng came up with the idea to use the characteristics of "seven days in the sky and a thousand years in the world" to build an underwater city that constantly changes its location every day so that it cannot be found in the divine world. The two of them suppressed their magic power and lived in the Undersea City for a long time. However, one day, a rare disaster will occur below the Undersea City. In order to protect the people from harm, Xifeng and Shuibi decided not to change the location of the Undersea City for the time being, and use this city to suppress it so that the disaster cannot happen. But because of this, the heavenly soldiers and generals of the God Realm quickly found their location. Faced with the coming disaster and the pursuit of soldiers, both of them calmly chose to risk their lives to ensure the safety of one party. Since Xi Feng is a demon, he can regroup his body and resurrect after death, but Shui Bi is really dead