Kingdom of Camelot

is the new yet prosperous kingdom to the far south of Britannia led by the current king, Arthur Pendragon who is advised and mentored by the Boar's Sin of Gluttony, Merlin of the Seven Deadly Sins. Following the battle between the Seven Deadly Sins and the Demon King in Meliodas' body, Camelot was completely wiped off the face of Britannia. However, after defeating Cath Palug, Arthur set out with Merlin to rebuild Camelot as an "everlasting kingdom".

Sixteen years after the defeat of Demon King and Cath Palug, Camelot was rebuilt within an alternate dimension created by Arthur using the power of Chaos and has since become the enemy nation to the Kingdom of Liones due to their ideological differences, putting the two nations into direct conflict and setting the stage for a new war to begin for Britannia.

Background
Not much is known about the Kingdom but it is said that Uther was once the king of Camelot before Arthur's ascension to the throne and had an alliance with the Kingdom of Liones.

At some point, Arthur became the new king of the country after pulling out the Sword in the Stone that fell from the heavens when no other Holy Knight can pull it out.

Plot
When Bartra suffered a stomach ulcer, Arthur and Merlin returned with him to Camelot to have him treated with a Cure Angel which would eat away the tumor despite the discomfort of the Liones' king.

Later on, Arthur led the kingdom's Holy Knights in defense of their country against an Albion, a massive behemoth awakened by the Ten Commandments' return from the Demon Clan's seal.

During the advancement of the Ten Commandments in the conquest of Britannia, Camelot is taken and placed under the control of the Demon Clan by Zeldris, who managed to overcome his military forces by himself. In spite of the efforts of Arthur and his soldiers, Camelot becomed the headquarters of the Demon Clan.

During the new Holy War, Camelot ends up being destroyed during the battles between the Seven Deadly Sins and the Four Archangels against Zeldris, the Original Demon and the Demon King.

Following the destruction of the Demon King, Merlin brings Arthur's body to Lake Salisbury to revive him as the "King of Chaos", where he is ambushed by Cath Palug in an attempt to steal Chaos' power and during their second fight, he is horrified to learn of his kingdom's destruction and left in despair but thanks to the Seven Deadly Sins and Elizabeth coming to help, he regains hope and plans to rebuild Camelot as an "everlasting kingdom" in opposition to Cath's ideology that everything in this world is doomed for eventual destruction.

Arthur finally used the power of Chaos to reconstruct Camelot in an alternate realm altogether, hoping to turning it into a paradise where humanity could live happily. However, it turns out that every creation in this new Camelot results in the destruction of something in Britannia. Thus, over the course of sixteen years, Britannia was slowly being deprived of things like mountains, forests, lakes, and even entire villages, which according to Meliodas would eventually lead to the destruction of the whole world.

As a result of Arthur's ideology against coexistence between humans and other races, the entrance to Camelot is protected by a barrier that prevents any race other than humans from passing through. The entrance to Camelot's dimension can only be opened by the power of marks that Arthur places on the bodies of his Holy Knights, which are activated by the wearer's life force and incantation.

Trivia

 * Camelot is the seat of power of King Arthur and the Knights of the Round Table in Arthurian legends.
 * According to Hendrickson, the old Camelot was a growing power that might have the potential to be on par with or possibly greater than Liones, believed to be the second strongest nation after Liones itself. Following the restoration of Camelot in an alternate dimension created by Arthur, it has now become Liones' rival in both power and ideology.