digitalbusker quoted The Hero of Ages by Brandon Sanderson (Mistborn Era One, #3)
To end the Final Empire and restore freedom, Vin killed the Lord Ruler. But as …
Content warning Spoilers for Mistborn: The Hero of Ages
"Perhaps she was never the Hero," one of the others offered. Sazed shook his head. "I believe that she is. These prophecies still refer to her--even the unaltered ones that you have told me. They talk of one who is separate from the Terris people, a king of men, a rebel caught between two worlds."
— The Hero of Ages by Brandon Sanderson (Mistborn Era One, #3) (Page 636)
You didn't mention the one about the Hero being tall. And even if there's some linguistic quirk of the ancient Terris language that makes "king" gender neutral, that's a stretch for Vin. In short, Sazed, you are suffering confirmation bias.