In the past, the world was bundled with demons by the evil dragon Diabolos, and demons were ferocious. However, 14 years ago, Diabolos is defeated by Zard, a boy who was called a hero at the age of seven at the time. He calmed down the demons, and returned the world back to its peaceful state. Four years later, however, Diabolos was resurrected and the demons began to attack the world once again. Zard headed to fight Diabolos again, but he never came back.... On 4996, Kai, Zard's best friend, traveled to see whether what Zard said about humans and demons coexisting together was possible. During the journey, he meets Izayoi, a strange boy who can speak to demons with his heart; and Gend, a brown-skinned swordfighter who seems to be a survivor of the Dark Elves race. Kai discovers that perhaps, they are the key to the coexistence of humans and demons, which led to him traveling together with them. (Source: TMDB)

In modern day Tokyo, three university students, Negishi Miyako (Neko-chan), Saiki Haruka, and Yamagishi Keiichiro, have magical powers that make them feel like outcasts. They come together one night and are transported to another world. They open a massive door and Neko finds that she is the Princess Neryulla, who must defeat the evil Duran III to free her people. (Source: AniDB)

Isami Hanaoka is just a fifth grader who happens to be a descendant of the Shinsengumi. Together with fellow descendants and classmates Soushi Yukimi and Toshi Tsukikage, she discovers in the basement of her home, strange artifacts left behind by their ancestors as well as a message urging them to Fight the evil Kurotengu organization. (Source: ANN)