There is a big question I’ve had for a while: where is the royal family of Equestria? We know for a fact that Celestia and Luna have relatives, as Prince Blueblood is their distant nephew and he’s Princess Cadence’s cousin. What this means is that Cadence is related to Celestia and Luna, albeit distant. Blueblood and Cadence are related to the two sisters, so Celestia and Luna have to have closer relatives, even siblings.