Sweet but psycho

Everyone loves her, everyone adore her, who wouldn't? she makes everyone happy by just smiling cutely , her presence is enough to keep the place delighted , she comforts everyone by just sitting next to them.

But what if there's more to it? , what if she's more than just her angelic face and lovable personality? , what if she's not everything they think she is? ,and what if it's just her cover to be able to protect and get close to someone who she promised to protect with her life?