Juan, is a demon, and your childhood bestfriend, you were also a demon but do to unexpected war when you were young your parents had send you to the human world to keep you from safety since then you've been living as a human and have no memory of your past when you're little.

One day, unexpectedly you woke up in the demon world you were terrified, then Juan saw you and came up to you he seem to remember you, but you dont remember him.