Novoland: Castle in the Sky series never fails to amaze me. Great movie. The cinematography is superb. The story somehow made me understand Feng Ren more. Also, Fang Ruche is not in any way related to this story. This is Feng Ren's back story which happened way before the timeline of Novoland Castle in the Sky 1 and 2.

And since the given plot summary is inaccurate and somehow confusing, here is a clearer version.
--- Feng Ren declares war on the Human Tribe. Seeing that the Human Tribe has no means of retaliating, Fang Qiwu (portrayed by Wang Yu Wen), the queen of Human tribe, tries to use a time machine device to return to the past so that she can possess the body of Nan Yinmeng, Feng Ren's beloved consort, and kill Feng Ren (portrayed by Chai Ge). However, when she wakes up in another timeline, she is told that Feng Ren is dead. However, Fang Qiwu refuses to believe this and merely think this is a rumor. The body that Fang Qiwu wakes up in turns out to be Hong Luan (portrayed by Chong Dan Ni), the top beauty of the Human Tribe. In ten days, she is to marry Feng Qi (Li Dai Kun), the crown prince of the Yu tribe (also brother of Feng Ren). As it is told in history that Feng Ren would play the Qin during the wedding ceremony, Fang Qiwu (as Hong Luan portrayed by Chong Dan Ni) plans to kill Feng Ren during her wedding day. During the ten days, she is protected by a man named Nan Feng. Fang Qiwu falls in love with Nan Feng as both share the same love for music. However, just a few days before the wedding ceremony, she finds out that Nan Feng's true identity is actually Feng Ren.