Spoilers from the fourth episode of Utawarerumono - Futari no Hakuoro (since it's airing now).
In this episode a princess just returned from another country with a memory loss; the country she returned from is now in political upheaval, and the princess' country plans to invade it.
After regaining her memories, she tries to get back to that country to help her friends, but towards the end of the episode her father and aids stops her, saying to look at the big picture; she then asks her father to appoint ther as head of the invasion forces, and while asking this she changes voice from a soft one to a more strong one, and shifts from わたくし to われ.
I tried to understand the implication of this shift in referring to herself, but I wasn't able to understand it; so I was wondering, what kind of implications could have shifting from わたくし to われ?