For Chapter 00 - Prequel, the serial killer on the train is singing a verse from Beethoven's Symphony No. 9.
Freude, schöner Götterfunken
Tochter aus *Elysium,
Wir betreten feuertrunken,
Himmlische, dein Heiligtum!
Deine Zauber binden wieder
Was die Mode streng geteilt;
Alle Menschen werden Brüder,
Wo dein sanfter Flügel weilt.
Joy, beautiful spark of divinity,
Daughter from *Elysium,
We enter, burning with fervor,
heavenly being, your sanctuary!
Your magic brings together
what custom has sternly divided.
All men shall become brothers,
wherever your gentle wings hover.
*Elysium is an ancient Greek version of the afterlife. Unlike Hades, those allowed to enter Elysium must be mortals who are related in some manner to the gods or heroes of ancient Greece.