Stoker describes Dracula as a Szelkely. He was in no way connected to Vlad Tepes.
The Szekelys (or Szeklers) was a distinct group that emerged in Transylvania from among the Hungarian tribes, which moved into the area at the end of the ninth century. Others suggest an independent origin, possibly a lost group of Bulgars who had invaded the area in the seventh century. Szekelys claim a pre-Hungarian origin. Originally they settled in southeastern Transylvania, but in 1224 A.D., they migrated northward and relocated in the eastern mountains. The Szekelys formed a first line of defense for the Hungarians who controlled the Transylvanian plain to their west, and they developed a reputation for their bravery and fierceness in battle. (Had this saved, don't have the source)
I honestly think his distraction concerning his love interest was what caused his downfall. He put himself in harms way because of love. He thought he was all powerful and no one could stand against him because of his powers. As far as blood typing they must have been doing transfusions or be in the beginnings of that or how else would Stoker have thought of it? So I looked it up.
"In 1901, Landsteiner found that blood from two different humans, when combined, would sometimes "agglutinate," or form clumps, rather than smoothly mix. On further research, he discovered that blood cells are coated with immune response cells, called "antigens" and "antibodies." If they do not correspond appropriately, like keys fitting into their locks, a sometimes violent immuno-response occurs, which can include hemolysis (destruction of red blood cells) and kidney failure.
The discovery of blood types earned Landsteiner the 1930 Nobel Prize in Medicine. Prior to his breakthrough research, mismatched blood transfusions had been routinely killing people for over a century."
http://www.bookofodds.com/Health-Illness/Organ-Transplantation/Articles/A0822-Blood-Types
