Re: The Age problem ?
Read the entire post you quoted next time. I said that the databooks give more information than the manga has room to provide. Regardless of your own personal feelings they are just as much of the story as the manga itself, since Kishi is the one that pens them.
As for being something ordered by the publisher, Kishi isn't the only mangaka creating databooks. Kubo has the "Masked" databooks, Oda has databooks as well for One Piece. All are used simply for background information (I'll keep repeating that point until it sinks in, fyi) that the author doesn't have time to convey in the manga.