Here's my headcanon for Alicorns, present in my upcoming story: "Darkest Darkness". Up next: My notes on Necromancy.
Alicorns
Alicorns are undoubtedly one of the most exquisite races ever to have lived in Equestria. While their origins remain unknown, Princess Celestia and Princess Luna have agreed to answer most, if not all, questions regarding their race; from their culture and civilization, to their mysterious destiny-related cutie marks.