Someone has a whole theory somewhere (I don’t think it’s on this site) that Rumple’s son became miserable after Rumple became the Dark One and made a wish that he could disappear that the Blue Fairy overheard. She somehow found a way to make him disappear and he became one of the Lost Boys from Peter Pan who never grows up and is befriended and protected by Tinkerbelle (another Fairy). He is somehow spared from the curse but finds out about it. This person thinks that Rumple wrote the book and that the reason that Henry can’t figure out who Gold is is because he left parts of himself out of the book. Rumple’s son (who didn’t die because he never grew up) starts to age when Emma comes on the scene and figures out what is going on (he is August W. Boothe). He comes to town and adds the missing pages that contain Rumple’s story so that Henry can figure out who Rumple is). It explains why Rumple hates Fairies so much. Sounds like a decent theory to me and one I hadn’t thought of.