Underground River

"Underground River" is an insert song from the anime. It was composed by Kevin Penkin and features Raj Ramayya as the vocalist. It was played for the opening credits of the first episode. The lyrics are in English.

Lyrics
''Travelling the aether back to you To a land so far away I feel the distance in between''

''A fragment of the world that used to be Speaking through the river stream Calling to me Luring me down''

Though I know just what I am Who I could be is the mystery to solve

''I shall find The underground river's soul''

''Let it shine and let it glow Let it shine The underground The underground river has shone''