Éowyn (played by Miranda Otto) is the sister of Éomer in The Lord of the Rings.  She is a minor character introduced late in the series.  She is at first enamored of Aragorn, though she eventually goes on to marry Faramir.  Éowyn is incredibly strong-willed and eventually impersonates a man in order to fight with her fellow countryman.  She saves King Théodon's life and kills the Witch-King of the Nazgul, who a prophesy had said could be killed by no man.  If you're willing to really commit to your costume, feel free to dirty up your outfit and tatter your cloak for a more authentically used look.

123456789