What is the most legendary dragon?

I must inquire, what is the most renowned dragon that has captured the imagination of countless cultures and tales throughout history? Is it the wise and benevolent dragon, a protector of treasure and knowledge, or perhaps a fearsome and destructive beast, unleashing its wrath upon unsuspecting villages? Could it be a dragon of great size and strength, with scales as hard as diamonds and breath that can melt steel? Or does the title of most legendary dragon belong to one that embodies a unique blend of these traits, a creature that stands as a symbol of both power and mystery? Surely, such a question deserves a thoughtful and detailed response.