Eivor is the name used for the protagonist of Assassin's Creed Valhalla.
Released in 2020, Valhalla follows Eivor, a Viking raider who leaves Norway and becomes involved in the settlement of England during the ninth century. The player can choose a masculine or feminine presentation for Eivor, but the character's name remains Eivor.
Eivor's clan establishes Ravensthorpe, a settlement that grows as alliances are formed with English kingdoms and other groups. The story also connects Eivor to the Hidden Ones and to the larger Isu mythology that runs through the franchise.
Bayek is from Origins, Shay Cormac is from Rogue, and Jacob Frye is from Syndicate. Those protagonists belong to different historical periods and games, so the short answer “Eivor” identifies Valhalla's central character without relying on the player's chosen appearance.