I felt it was Ignazio as narrator for two main reasons: Asterios was so often and regularly betrayed by the narration, and not in the self-serving ways, I thought. These betrayals are what all writers have to do to present their characters to the reader.

Also, the narration takes a competitive brother’s relish in what happens to him, even when it is wordless, or perhaps most especially, in the cruel dreams of him as a failure in Ignazio’s presence. It does go on after his apparent death, which is the only thing I can find that would suggest the the reading you speak of, but who can kill a ghost in a dream? I don’t find any support for your reading otherwise, thus far, but I’ll think about it.

A couple of notes about the color: the “previous unseen colors” you describe appearing in the last section of the book are the result of the color schemes of the two previous timelines coming together. Asterios finally reconnects with Hana, the blues and pinks of the one timeline commingling with the yellows and purples of the other to create greens and oranges (along with the yellows, blues, pinks, and purples). That the dream is rendered completely in purple speaks to the power of the subconscious images to “both” Asterioses: the one now and the one who had been married to Hana. It is the one color that is in both timelines, coloring those worlds as the shape of the narrative, concluded by a lightning bolt that also precipitated the narrative’s action, is affected by the myth of Orpheus.

One last question: Is Ignazio really narrating the novel? He seemed to me—whether Asterios actually had a twin brother who died at birth or not—a repository of Asterios’s wishes and self-criticism. Instead of Ignazio ghostwriting the book, I wonder if it’s not really Asterios who ghostwrites Ignazio?