Hiiro Ishibashi

Ruka is a young girl whose parents are separated and whose father works in an aquarium. When two boys, Umi and Sora, who were raised in the sea by dugongs, are brought to the aquarium, Ruka feels drawn to them and begins to realize that she has the same sort of supernatural connection to the ocean that they do. However, the exact nature of the boys' power and of the abnormal events is unknown, and Ruka gets drawn into investigating the mystery that surrounds her new friends. (manga)

The anime takes place in the futuristic town of G?ha and stars Y?ga ?d?, a fifth-grade, elementary school student, who loves both inventions and dueling. (TheMovieDB)

The general of an evil army trying to conquer Earth spends his days off enjoying the worthwhile things about Earth. (imdb)