Beelzebub: Lamia

 Lamia is a medical demon who works as a nurse of sorts for Dr. Rachmaninorr.  She came to the human world to treat baby Beel and later some of the others.  Lamia can be a bit bratty and sadistic a lot of the time; but, it is possible... if you can gain her respect, for her not to want to perform potently harmful experiments on you.  She has the ability to read minds and is protective of baby Beel.