What About Blueblood?

If there's one question I've always had during MLP, it's this; what role does Prince Blueblood have? Supposedly he's Celestia's nephew, which would supposedly make his mother Luna. Based on his age in season one, right after Luna is released from the moon, I doubt that he was born after Nightmare Moon's return. This brings up more questions;
- Who is Blueblood's mother? Luna? Some other royal? Or is he actually Celestia's, distanced with the title of "Celestia's nephew" because he brings her some form of shame?
- What role does Blueblood play? Does he actually do anything at all aside from look pretty at parties? I contemplated at one point whether or not he ran the agency that BonBon (sorry - "Sweetie Drops") used to work for, although I have no way of confirming or denying this.
- Were there ever plans to flesh him out? Sure, he may have just been a one-off character, but introducing a royal family member (and a male one at that, in a clearly female-dominated universe) isn't something one does lightly. He didn't appear to have any role at all in either of Twilight's coronations, despite Luna and Cadance being there in full royal regalia alongside Celestia.
This can be easily ignored- just some dumb ramblings from someone who thinks about the nuances of Equestria far too much. Oh and yes, I'm aware that Lauren Faust briefly explained it... personally, though, I'd like to believe that there's more to him than that.