The fainting thing is overused, especially in anime. In real life, it indicates a medical problem.
Still, young Harry has had quite a shock.
Last I heard, proper address to a Duke in England was "your Grace". Dukes have their own court and the right to their own army. Their relative rank is higher than even princes, except the crown prince. They have their own crown.
The above is , of course, subject to alteration. :)
Enjoyed it.
Author's response
yeah I know it's overused, but it's funny. And how does it indicate a medical problem in real life?
Yes he has had quite a shock, you would've to if you had found you were descended from the two most famous people in British lore.
I'm not yet comfortable with having him called "Your Grace". He probably will end up being called that, but not right now.