The theme song for "Innocence", "Follow the Nightingale", was created and sung by Japanese singer-songwriter Kokia. She was asked on board by the game's staff as they were favorably impressed by her voice. While composing the song, she was allowed to draw inspiration from storyboards and early footage. The theme and lyrics of "Follow the Nightingale" tie in with the characters' status as people reincarnated in the game's present, focusing on the main protagonist Luca asking why they were reborn. As with some of her earlier songs, she wrote some parts of it in code, with Kokia herself describing them as "perplexing riddle words". For "Innocence R", Kokia was brought in again and asked to create a different opening number, "New Day, New Life". For this song, Kokia drew from the opening sequence, where Luca wakes from dreaming of his past life and opens the window. Unlike "Follow the Nightingale", "New Day, New Life" was written entirely in standard Japanese, as she wanted to fully convey Luca's feelings in the song, along with those of Kongwai.