Totsuka Maria was praying in a chapel at Seiseki Girls' Academy when a black cross comes falling from the sky. On that cross, was a fallen angel, bearing the sin of pride, Lucifer. Maria attempt to tend to the angel, but the floor falls out and she disappears. Lucifer finds herself in the depths of hell, and runs into the Demon Lord of Envy, Leviathan.
I'm going to follow you
from now on, Onee-sama.
Von nun an werde ich
dir folgen, mein Herzchen.
Te seguiré desde ahora.
Te seguiré desde ahora.
Je serai toujours à tes côtés,
Lucifer !
Da ora in avanti ti seguirò ovunque, Mia Signora.
A partir de agora sou 
sua devota, Onee-sama.
Теперь я всегда буду 
следовать за вами, сестрица.