The end of terminus enters its final days. Iruma safely finishes his homework and is invited by Sullivan to go to Magical Street along with Opera. They browse around picking up things Iruma will need for his new school term. Iruma happens to overhear some demons talking and then asks Sullivan about the Demon King, since he is one of the most qualified individuals to become Demon King. What exactly does it mean to be the Demon King, the most powerful being in the netherworld?
Because the Demon King 
is the netherworld itself.
.لأنّ ملك الشّياطين هو الجحيم نفسها
Der Dämonenkönig selbst
ist nämlich die Dämonenwelt.
El inframundo es un reflejo
del Rey Demonio.
El inframundo es un reflejo
del Rey Demonio.
Car le Roi-démon
est l’enfer personnifié.
Perché il Re dei Demoni è l'Altro Mondo.
O Demônio Rei é o mundo inferior.
Потому что Князь —
это и есть Преисподняя.