The Melody of Oblivion (忘却の旋律) is a Japanese manga series by Shinji Katakura. The series was published through Kadokawa Comics through Shōnen Ace between 2002 and 2004.
An anime television series adaptation produced by Gainax and animated by J.C.Staff aired between April 7, 2004, and September 21, 2004, on TBS. A Game Boy Advance game was published through Bandai for Japanese markets.
Synopsis
Approximately a century ago, during the 20th century, humanity waged and lost a war against creatures called "Monsters", who were able to assume human form. Now, approximately a century later, humanity is aware of the Monsters' existence but not that there was ever a war, the latter of which was deliberately orchestrated by the Monsters. Humanity's only protectors against the Monsters are the Warriors of Melos, a group of warriors capable of seeing a seemingly mute young girl called "Melody", who appears at important times. These warriors are aided by devices called Aibar machines, futuristic modes of transportation capable of some level of sentience.
The series primarily follows Bocca, a teenager who chooses to become a Warrior of Melos and bring an end to the Monsters' tyranny.