"Theme of Rena" is the main theme of Star Ocean: The Second Story and Star Ocean: Second Evolution's female protagonist, Rena Lanford, played exclusively in a scene where she finds out about her past. Fitting to this, it's a sad but also cheerful melody.
"Theme of Rena" is a proeminent theme in the second Star Ocean, and is the only song that attempts to imitate, or in fact possess voice (with exception of Second Evolution's theme song). Its tune is used for various themes within the game, such as "The venerable forest" and the remix "Theme of Rena (music box)".