Cosmo the Seedrian

Cosmo (コスモ Kosumo) is a main character from the anime series Sonic X. She was a female child of a plant-like alien species whose home world was destroyed by the villainous Metarex, who, in the years that followed, left Cosmo as the sole survivor of her kind. To thwart the Metarex's ambitions for universal dominance, Cosmo joined Sonic the Hedgehog and his allies in their war against the Metarex, eventually becoming a love interest for Miles "Tails" Prower, but she sacrificed her life to defeat the Metarex for good.