Sonata wa Ittai Dare Nanda Anime Details and Episodes An "unknown boy" has defeated the Demon King and saved the world. The whole world waits to learn of who he is, but it turns out the boy himself has… Series info Watch free DetailsFormatMangaStatusFinishedSourceOriginalCountryJapan GenresActionAdventureDramaFantasy TagsAmnesiaDemons RecommendationsSousou no FrierenKaiten no AlbusLord Magear no DeshiThe Awakening of a Great Saint: Waking up as a Legendary Great Saint after Twenty Years of Miasma Purification