In God of War (2018), the optional Valkyrie Queen boss is named Sigrún.
Sigrún is encountered in the Council of Valkyries after Kratos defeats the game's eight other Valkyries and places their helmets on the thrones there. Unlike the regular Valkyries, she combines attacks and abilities associated with several of them, making her one of the game's most demanding optional battles.
The Valkyries are powerful supernatural warriors connected to the Norse afterlife. In the game, they have been corrupted and imprisoned by Odin, and Kratos helps release them by defeating them in hidden arenas across the realms.
Sigrún is sometimes confused with individual Valkyries such as Gunnr, Hildr, or Róta. Those names belong to separate encounters; Sigrún is specifically the Valkyrie Queen and the final challenge in that quest line.