This crazy Wizard/Inventor named Zhuge Liang invented hot air balloons and used them as communication between troop formations. No wait, this one is actually true and not a legend.

He’s also the guy after whom the “zhuge nu” (which you may also have heard called a “chu ko nu”—a repeating crossbow) is named. Though it seems likely that he was actually not involved in inventing it.

Since you brought up Vlad III, it’s probably worth noting that claims that he “inspired” Bram Stoker’s 1897 novel are grossly exaggerated. The truth is that Stoker had pretty much finished the novel and was just weeks from publishing it—under the title Count Wampyr—when he came across stories of Vlad the Impaler, and decided to change the name and a few minor details to fit.