The Sky and His Sun (KHR R27 Fanfic)

Where Tsuna is the Sky Arcobaleno, and sky arcobalenos look like teenagers who don't age or die. He is not the Vongola Decimo. The question is, if Tsuna and Reborn were together in the past, why did they decide to part ways after becoming Arcobalenos? R27/slight All27. AU. Follows canon's plot but will skip the parts that are deemed as unnecessary. [Katekyo Hitman Fanfiction]