Xehanort referred to Eraqus as a blueblood in one of the Secret Reports. Blueblood is a descendant from the Keyblade War Era/Keyblade Line/Dandelions (Blue Blood is normally referring to Nobility anyway.) The later Secret Reports very strongly imply that Luxu
I see, if I understand this correctly everyone coming from the X-era as well as those who have become wielders because of them are "bluebloods"?
This would then include Ephemer, Skuld, Lauriam, Elrena, Luxord, Demyx and Ventus directly from the X-era and probably Aqua, Terra, Kairi and Riku due to furthering the line.
Sora, Roxas and Xion would then be an interesting case as they didn't get their keyblades the regular way.
If there is or ever was an actual individual named Braig/Xigbar or if it was always Luxu speaking and acting is indeed an important question.
And now I do realize that him constantly referring to the "angry look" from Ventus (and later Sora too) may go further and deeper than the chronological first time we see during the finale of BBS.
Heck, him seeing Xion as Ven in Days may also have deeper reasons than thought so far.
If he's indeed the new main villain in the second saga I think that's what's called a "Dragon Ascendant" trope since he posed as Xehanort's right hand man/dragon for all the time yet now takes center stage.