Final Fantasy XV is the fifteenth main installment in the Final Fantasy series. It is an open world role-playing game set in the fictional world of Eos. It is almost entirely ruled by the empire of the militaristic Niflheim, except for the kingdom of Lucis. The Lucians have been able to keep Niflheim at bay, mainly because the capital Insomnia is protected by the Wall, a magical shield powered by a crystal. At the start of the game an armistice is proposed as well as a union of states through the marriage of Prince Noctis of Lucis and Lady Lunafreya of Tenebrae, a separate nation with limited political power due to the influence of a priestess called the Oracle. The game opens when Noctis, the only playable character, travels with his friends Gladiolus, Ignis and Prompto to Accordo where the wedding is to take place. Along the way it is revealed Niflheim has betrayed Lucis and the crystal has been stolen with many important figures killed. Noctis' main quest becomes to reclaim the throne and rescue the crystal.