The opening theme, Lilium, was composed by . Its lyrics were arranged by Kayo Konishi (they are a group called MOKA☆). The lyrics are taken from biblical passages in Psalms, the Epistle of James, and the Renaissance hymn "Ave mundi spes Maria", in Ecclesiastical Latin. They are arranged in the style of a Gregorian chant. The lyrics also contain the phrases "Kyrie, fons bonitatis" and "Kyrie, ignis divine, eleison", which are a mix of Greek and Latin words, from a passage in an alchemical mass written by Nicholas Melchior in the Theatrum Chemicum. "Lilium" is performed by .