Dishonored: Death of the Outsider

After the events of Dishonored 2, Emily Kaldwin is reinstated as empress and begins to salvage the Empire previously broken by Delilah's rule. Billie Lurk wakes aboard her ship, the Dreadful Wale, having a recurring nightmare regarding her right arm and eye. Billie has tracked down her old mentor Daud's whereabouts to a boxing club in Albarca Baths. She makes her way there, finding that the boxing club is run by a Void-worshiping cult called the Eyeless.
Billie witnesses Daud restrained by a device that cancels out his supernatural powers. She disables the device, freeing Daud. Daud is happy to see Billie and asks for her help in killing the Outsider, to which Billie agrees. On the Dreadful Wale, Daud explains that the Eyeless are in possession of a ritual knife that was originally used to create the Outsider thousands of years prior. Daud believes that the knife can be used to kill the Outsider. Billie is visited by the Outsider, who replaces her right arm and eye, granting her supernatural abilities.
Billie investigates the leadership of the Eyeless. She discovers that the knife is contained in a safety deposit box in Karnaca's largest bank, and steals the keys to the deposit box from the Eyeless' leaders. Billie infiltrates the bank and steals the knife, upon which the Outsider appears and reveals that Daud has died of natural causes aboard the Dreadful Wale, to her dismay. She returns to the ship and burns it down, cremating Daud's body.
Billie infiltrates the Royal Conservatory, where a former Eyeless leader had hidden important documents. They detail the location of a Void portal at an abandoned mine outside Karnaca. Billie travels to the mine, which is overseen and operated by the cult that created the Outsider. Billie learns from their notes that the Mark of the Outsider is actually his name, written in an esoteric script that only the dead can read. Billie makes her way to an artifact called "the Eye of the Dead God" and absorbs it, allowing her to safely enter the Void portal.
Inside the Void, Billie makes her way to the Ritual Hold, where the Outsider resides. There she finds him bound and immobile. Billie can then either return the Outsider to the mortal realm by having Daud's spirit pronounce his real name, or use the ritual knife to kill him. Either way, the Outsider is displaced, and Billie acknowledges that with the Outsider gone, the world will be changed, as there is no longer anybody who can decide who will receive the Void's power.