User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-75.71.34.254-20150313003207

Ever wonder about the apples? I noticed apples seem to have a special, as yet undefined, place in DxD. When Koneko gets sick, Ravel offers to make a dish from the special apples grown in her territory that had just arrived, Tannin becomes a devil so he can get the dragon apples needed by a certain race of dragons and in volume 18 the First Bael offers to serve Issei and Rias a "piecake" made from the special apples from the Bael territory.

Maybe this is nothing, but it does seem to be a recurring theme. Aside from the obvious biblical reference, has Ishibumi ever stated the apples to be of any significance?