No they are not real...Drinking blood is an obsession but it has its drawbacks...we know that blood is made from red globuly(the actual blood) white globuly(part of the limfatic system) and more components...when you drink blod it coagulates and the acid in you stomach digets it thus releasing high ammount of iron witch the human body cannot wistand and thus you will automaticly and withought any restrain...throw up.Blood dosent contain much nutriments and you can only drink 100 ml of it before you get sick.And if you somehow drink it and the white cells somehow survive all that acid..they will start terminating your intestinal flora witch will cause an acute diarrea
Edit:I am just a self obssed paranoid agrgresive human beeing that like to terrorize the others just to feal theyr pain witch brings me happines and joy but now you cought my good side