Napstablook x Yandere!Reader

Just a few years ago, the monsters were released from the underground. You, of course, eventually befriended a few, but you never dated any, for no one really caught your eye....Until you met them... At that moment, nothing and no one else mattered, all you wanted to do was to protect him, to make sure that he was yours and yours alone. And to make sure that no one else got in your way.