Well, at some point, just how author started the story, it really looked like Xun and Ao were the main couple but the author posted in weibo, the center of the story is Shang. If not for Shang, there's no love story between Ao and Xun.
As for me, I really like Mixi and Shang's story better. Given how Ao and Xun are childhood lovers, I think theres no more to tell about them. They already fixed their issued in the future chapter as well. A small peak of their lives would suffice. As for Mixi and Shang, their love story still have a lot to face. (▰˘◡˘▰)
I dont know. Some might disagree, but I somehow prefer the ghost cause he craves the bottom (i cant say genuinely,.though) but now, this bff only forced himself to sleep with him.