Back at the Rumor topic, people started debating over Dracula being defeated by anyone, and I've my own speculation about it, which is, only Dracula's power can match his own power. The Vampire Killer is also part of his power.
It goes like this:
Everyone here is familiar with Lament of Innocence, so everyone knows that Mathias became a vampire by using Walter's soul. Now, the Vampire Killer is a part of Walter, who vampirized Sara. This means that the soul contained there is imbued with Walter's power, which is now Dracula's. So this means that the Belmonts have been using Dracula's power against himself all this time.
What about the other heroes, you say?
Alucard? Dracula's blood, even possesses some of his powers.
Hector? Dracula's direct apprendice. Learned his trade with Dracula himself (and possibly acquired some of his dark power manipulation).
Shanoa? Dominus.
Another detail is that Jonathan apparently used the Vampire Killer to banish Dracula, canonically.
All others are not canon, so I'm considering only canon battles. Also, I'm setting aside gameplay-related info, like the Vampire Killer being "holy" even though it's a vampirized soul inside it.
Finally, I think "normal" attacks can weaken him, but only a death-blow dealt with his power can banish him, as seen in Order of Ecclesia, where only dealing high enough damage (9999) BEFORE the death blow with Dominus can Dracula be destroyed.
What do you think?