Dantalion, one of the many candidates for Lucifer's throne, decides to live in the human world an attend William's school and lobby the young noble to choose him as Hell's ruler, but he gets more than he bargained for when William's friend Isaac accidentally summons one of his competitors!
You two, keep your eyes
on William at all times!
¡Ustedes dos, no le quiten 
la vista de encima a William!
¡Vosotros dos, no perdáis de
vista a William!
Mantenham os olhos grudados no William!