This is a great piece of fiction. All the UFO characters save Nue are given detailed (and sometimes tragic) backstories of their own, explaining how they all came together. Shou's development as a person also cannot be missed; though listed as Shou/Nazrin, the story is less focused on shipping than it is on Shou's growth. It was also completed recently, so you can read it straight through without waiting for updates!
Sakura Rurouni's review of the Touhou fanfic
This is a great piece of fiction. All the UFO characters save Nue are given detailed (and sometimes tragic) backstories of their own, explaining how they all came together. Shou's development as a person also cannot be missed; though listed as Shou/Nazrin, the story is less focused on shipping than it is on Shou's growth. It was also completed recently, so you can read it straight through without waiting for updates!