The embodiment of love.
Shes isn't like her aunts a physical alicorn bound to a worldly entity, but an emotional alicorn bound to the emotions of this world.
Shes not strong, or adept in magic, as many ponies might think of alicorns. No, the first time she embodied her element the world fought for her love. Ponies would travel leagues to see the goddess of love, and propose for her hoof in marriage, Some more forcefully than others, the Changelings...
That is how the war happen, she didn't know how to return to her smaller form, she was stuck, as cities burn down for her sake. The changelings saw her as the largest battery of love, perfect for their hive, they needed her. She escape. She escape, the grasp of nobles and barbarians who tried to take her by force.
Far away she flew resting with the wildlife in the forest that kept her safe.
Celestia found her, and taught her how to control her powers, that was the last time she embodied her Love.
Now she must wield her power once more for the sake of Equestria. With Shining Armor, her champion, by her side, and her limitless love to feed his power, they would be an Unstoppable duo. For her beauty ponies and creatures alike will gladly fight to protect. Not this time, for her ties to the emotions of creatures she will inspire them to fight for their loved ones, not her. She can control it now, the ties of love that solidly bound her world, and her life.
So dragons best be ready, "Mi Amore" Is coming.
Solar Flare [link]
Nightmare Moon [link]