Lucina  

Future Witness, Lucy, Marth, Princess of Ylisse, ルキナ

Lucina is a princess who comes from the future and has a mark on her left eye called Naga's Brand of Exaltation. She values justice and believes it's her duty to save the world. Her father, Chrom, is very dear to her, and she often worries about him. The Parallel Falchion, which Lucina wields, was initially believed to be a different sword from Chrom's Falchion, but it was later discovered that they are actually the same weapon brought back from the future.