Overview
Zireael is Ciri's silver sword in The Witcher IV. The name means "Swallow" in Elder Speech, the ancient elven language. It is also Ciri's nickname and the subject of Ithlinne's prophecy about the fate of the Elder Blood carrier.
The gwyhyr
Zireael is a gwyhyr, a type of blade considered the finest in the Witcher world. Gwyhr blades were forged exclusively by the gnomes of Tir Tochair, and by the time of the novels, the gnomes had ceased production over 200 years prior. A genuine gwyhyr is extremely rare and valuable.
The blade is made of dark iron with a shape resembling a flame, typical of gnomic tradition. It is decorated with engravings of flowers and a tower. The inscription on the blade reads: "Dubhenn haern am gladeal, morc'h am fhean aiesin," which translates to "The flash that cuts through darkness, the light that breaks the night."
History in the novels
In late 1267, a sword salesman named Esterhazy gave Zireael to Ciri in the town of Fano. At the time, Ciri had been captured by the bounty hunter Leo Bonhart, who forced her to fight with the sword in the Claremont arena, sometimes under the influence of the drug fisstech.
Early in 1268, during the assault on Stygga Castle, Ciri killed Bonhart with Zireael. It was an ironic end: Bonhart had been the one who arranged for her to receive the weapon through Esterhazy. After Bonhart's death, Zireael remained Ciri's sword.
In The Witcher 3
Zireael appears as a unique sword Ciri uses during her playable quests. In the witcher ending (the ending canonized by The Witcher IV), Geralt has a sword forged for Ciri and presents it to her. She carries it as her primary silver sword into The Witcher IV.