Disturbia (Yandere!Beel x reader)

love has always been a fickle thing for demons. not many have it, and the few that do, go insane from it.
Y/n is a psychologist. mainly for the devildom asylum erected by Diavolo in the hopes of encouraging demons with dangerous personalities to seek help.
but not all of them are crazy. not on the outside atleast.
Beelzebub was forcefully committed thousands of years before Y/n was born.
Y/n has worked with him from the beginning, trying to help him deal with the loss of his sister. some people may call her methods... unconventional. dangerous. But its seemed to work on Beel. hell, hes got two more sessions with her before he is allowed out of the asylum.
but looks can be deceiving, and even someone as smart as Y/n could never see what was coming next.