Well, what made Dracula a figure of horror in ''Olde England'' was the fact he was a foreigner, an eastern European foreigner, which automatically triggered a certain xenophobic reaction in ye olde English of the day.
The real horror was that he was an aristocrat who perpetuated himself literally sucking the life out of people around him and turning them into his slaves, and in that time and place many saw that as essentially a real thing.
The story became legendary because it tapped into certain fears of the day it was written in. It's evolved over time and the character has changed, becoming more of a tragic ir romantic figure to appeal to certain audiences, but at first he was a figure of horror based on the fears of the day.
It's like why 'invasion of the body snatchers' and 'the blob' were so popular in the 50's, they tapped the commie scare of the day.
Now that you've read Dracula, try Carmilla, a contemporary vampire story that was even more salacious in it's time for it's lesbian theme.