Heirs to the Crystal Empire, aka I gave Flurry Heart siblings
Their names are Noble Heart (earthie), Sky Shield (pegasus) and Spell Shield (unicorn). Sky and Spell are twins, with Sky being a few minutes older.
Some more info below👇
Flurry actually takes more after her dad’s build when she grows up, while Noble takes after their mom. So as adults, Flurry is bigger and more muscular, while Noble is much more lithe.
Noble has a bit of an inferiority complex. For a long time, it was just him and Flurry and between the two of them, it’s safe to say Flurry pretty much won the genetic lottery. Having an alicorn for an older sister can often leave you in her shadow, especially if you have neither wings nor magic to wow others, which was exactly where Noble found himself. It left him feeling insecure and wishing he could add up to be a “worthy” heir to.
Noble gets along best with his cousin Bright Star, the both of them being younger earth pony brothers to an alicorn prince/princess.
The twins are frequently mistaken to be Twilight’s kids instead of her niece and nephew, it’s come to the point that it’s second nature for them to clarify that they’re Cadance and Shining Armor’s children.
Flurry and Noble were teenagers by the time their younger siblings were born, making for a huge age gap between them and the twins. Unlike with their cousins though, they have a close relationship with them. Flurry absolutely dotes on and spoils the twins while Noble takes his role as their protector and mentor very seriously.
Cadance’s alicornhood has had an interesting effect on the twins. Sky has some latent unicorn abilities in the form of weak teleportation magic, which allows her to teleport an object she has touched, though she can only teleport it to somewhere within a 20 mile radius. Spell’s latent pegasus abilities come in the form of being able to walkon clouds even without any cloudwalking spells, though only for 20 minutes at a time.
Noble spends lots of time with his aunts, and because of his insecurity, he really threw himself into his princely lessons and training in the hopes he could measure up to his sister. His great-aunts, whom he affectionately calls “Auntie Celly” and “Auntie Loony”, try to reassure him that he doesn’t need to keep pushing himself. Though on his particularly bad days, these well-meaning attempts at reassurance can make him feel like they’re pitying him, which just makes him push himself even more.
Sky likes spending time with her great-uncle (via marriage) Discord, even calling him “Chaos Uncle.” Discord is absolutely enamoured with the little pegasus and likes teaching her various pranks that she can pull. It’s because of this that she’s become a playmate and best friend of Flutters’ youngest child, Angel Cloud, whose family visits the Royal Family whenever possible.
Spell has a huge sweet tooth like his great-aunt Celestia, but in his case, he loves cupcakes. Whenever the Pie family comes to visit to either bake or cater for the Royal Family, he always asks for a cupcake from Pinkie, who’s always happy to oblige. He’s also made a friend from these visits in the form of Pinkie’s youngest kid, Chicory Root.