Found this on another site and I can totally agree
"To be honest, I never really considered XL as the third ml. He's much more than that. I like to think of the story as a narration of XL and XY's love tragedy. Here's a comment I came across while browsing online. (credits to the person who wrote this):
"相柳明明拿着男三的剧, 却演着男二的戏, 讲着男一的台词, 最后依然是男三的结局. 爱一人, 九命相抵."
"XL clearly holds the title of third ml, yet plays the role of the second lead, speaks the lines of the main lead, but ultimately has the ending of the third lead. Nine lives in exchange for loving a person."
A pretty accurate description right? "