Short answers, pulled from the story.
Éowyn is a fictional noblewoman of Rohan in J. R. R. Tolkien's The Lord of the Rings who describes herself as a shieldmaiden. She is the niece of King Théoden and sister of Éomer. She is best known for killing the Witch-King of Angmar, Lord of the Nazgûl, during the Battle of the Pelennor Fields.
Éowyn kills the Witch-King of Angmar after disguising herself as a male Rider of Rohan under the alias Dernhelm. When he boasts that no living man can stop him, she removes her helmet and reveals herself as a woman. The hobbit Merry Brandybuck then stabs the Witch-King behind the knee with a barrow-blade, and Éowyn strikes a killing thrust between crown and mantle.
The prophecy, spoken by Glorfindel, declares that the Lord of the Nazgûl will not fall by the hand of man. Éowyn fulfils it because she is a woman, not a man, and the Witch-King fails to anticipate this reading. The Tolkien scholar Tom Shippey compared this device to the witches' prophecy in Shakespeare's Macbeth, where Macduff's Caesarean birth similarly defeats his enemy's confidence.
Miranda Otto plays Éowyn in Peter Jackson's The Lord of the Rings: The Two Towers (2002) and The Lord of the Rings: The Return of the King (2003). Uma Thurman was considered for the role before Otto was cast. Otto also returned as Éowyn's voice and as narrator of Kenji Kamiyama's 2024 anime film The Lord of the Rings: The War of the Rohirrim.
In Old English, which Tolkien used to represent the language of Rohirric, eoh means "war-horse" and wyn means "delight," making Éowyn translate as "delight in horses." In Rohirric itself, her name would have begun with the element Lô- or Loh-, meaning "horse." Her alias Dernhelm combines dern ("secret, concealed") with helm ("helmet").
In the Houses of Healing after the Battle of the Pelennor Fields, Éowyn declares she will be a healer rather than a shieldmaiden, and will love all things that grow and are not barren. The scholar Melissa Hatcher, writing in Mythlore, argued this represents Tolkien's highest ideal of peace rather than an act of submission. Éowyn marries Faramir, they settle in Ithilien, and they have a son named Elboron.