At the center of Starfield's conflict are the Artifacts, mysterious relics that, when pieced together, allow the wielder to open the gateway to the Unity—the center of all space and time, and the place where every universe converges. Those who enter the Unity become one of a group of people known as Starborn, as they are reborn in another universe with greater power than before, including the ability to cross universes as many times as they wish. Needless to say, the Artifacts are a sought after prize, and three individuals seek them for their own reasons in the story of Starfield: the Hunter, the Emissary, and the player.
Source：https://www.cbr.com/starfield-why-three-protagonists/
