The Old Wall (第一魔法障壁, Dai ichi mahō shōheki?, lit. The original magic barrier) is a series of twelve towering statues built as a defense system strewn throughout Insomnia in the feature film Kingsglaive: Final Fantasy XV. Some of the statues also appear in the Windows and Royal Editions of Final Fantasy XV and Final Fantasy XV: Episode Ardyn.
Honoring the ancient kings of Lucis who dwell within the Ring of the Lucii, the statues animate when the Crown City is in danger at the behest of the current king, if they are strong enough, or one deemed worthy by the Ring of the Lucii. The statues wield giant versions of the royal arms from Final Fantasy XV, and once activated, act autonomously to destroy invaders.
According to the Final Fantasy XV Scenario Ultimania, the statues were created 2000 years ago to serve as coffins to each hold the soul of a dead king. From these coffins, the kings await the coming of the "Chosen King." The statues were also intended to serve as the Wall that protects the kingdom of Lucis.
When King Regis meets with the Lucian ruling council to discuss Niflheim's offer of peace in Kingsglaive: Final Fantasy XV, he reveals he is too weak to control the Old Wall from his premature aging through the New Wall draining his life force. During the fall of Insomnia, Nyx Ulric is deemed worthy of the power within the Ring of the Lucii, and commands the Old Wall to combat Imperial General Glauca and multiple massive Diamond Weapons. Though successful in stopping the general and the daemons, the cost of using the power of the Ring costs Nyx his life as per the agreement made with the Lucii.
In the Windows and Royal Editions of Final Fantasy XV, Ardyn, through unknown means, activates three of the Old Wall statues and uses them to halt Noctis Lucis Caelum and his retinue, using the Starscourge to force them to do his bidding. The party frees the rulers of yore from their corruption.
What happens to the Old Wall after Noctis uses the power of Providence to cleanse the world of Starscourge is unknown, but the Ring of the Lucii shatters and the Lucis Caelum bloodline comes to an end.
Three new bosses dubbed guardians of the Old Wall appear in the Windows and Royal Editions of Final Fantasy XV: The Rogue, The Fierce and The Mystic. However, they are much smaller than when depicted in the film.