Liones「リオネス Rionesu」 is a kingdom located in northern Britannia, that was ruled by the family of Liones before a coup d'etat at the hands of the Holy Knights, rendering it a puppet state. After the defeat of Great Holy Knight Hendrickson, the royal family was reinstated. The kingdom had an alliance with the Fairy Clan before the burning of the Fairy King's Forest 31 years ago.
The Kingdom is a large and powerful country which is protected by its knights and its order of Holy Knights. It was built over the vestiges of the Fairy King's Forest from Ancient Britannia. The Seven Deadly Sins were once an active group of knights in the kingdom before being framed for the murder of the Great Holy Knight Zaratras. It was revealed by Ban that the kingdom held a great treasure called Horn of Cernunnos which could summon a Goddess.
Ten years after the framing of the Seven Deadly Sins, King Liones, although realizing that a predicted Holy War would soon occur, ordered all the Holy Knights to lay down their swords in an effort to avoid war. However, the Holy Knights, believing that the war was inevitable and that protection of the kingdom was their duty, captured the king, with the current Great Holy Knights, Hendrickson and Dreyfus, assuming command. They also started enslaving and forcing the citizens to participate in military efforts while justifying their enslaving with the fact that the citizens were being forced to do something for their own protection.
The three Seven Deadly Sins - Meliodas, Ban, and Gowther - attempted to invade the Kingdom of Liones in order to rescue Elizabeth who was kidnapped. During their attack, an army from Camelot approaches Liones with their new king, Arthur. Hendrickson's Magic Research Facility building was completely destroyed during a battle between Diane and Dreyfus' Holy Knights.
Battles between the Seven Deadly Sins and the Holy Knights have caused significant destruction to all parts of the kingdom, forcing the regular knights to evacuate the citizens away from the battle as they could. The Deadly Sins and Holy Knight later join forces to stop Hendrickson and free Bartra and Elizabeth. After freeing them, Dreyfus was stripped of his rank due to his crime and Bartra was taken to Camelot for treatment as he was ill. But Hendrickson, after recovering from defeat, appeared by destroying a large section of the castle and awakened the New Generation's demon blood, turning them into Demons themselves, and began a rampage within the capital of Liones and its people, catching the Holy Knights and knights off guard. Various skirmishes broke out in the entire capital as the Holy Knights and knights immediately fought the Demons who were once their comrades but suffered heavy losses in the ensuing chaos to which Gustaf called it like hell.
Throughout the chaotic battles between men and demons, the entire civilian population were evacuated by groups of Holy Knights while their comrades fought against the Demons together with the Seven Deadly Sins. After the kingdom was freed from Hendrickson, the people of Liones slowly rebuild the kingdom and the Holy Knights went back to normal.
When the Ten Commandments begin their conquest of Britannia, they eventually invade Liones after several months. When the Holy Knights are unable to stop them or evacuate the royal family, the intervention of the Sins Meliodas, Escanor and Merlin gets that the Commandments are expelled from the kingdom, two of them being definitely defeated. The kingdom suffers several damages, mainly the castle that is destroyed completely. However, Merlin manages to repair everything by herself in one night. Several civilians and knights fell victims to the Piety commandment and moved to Camelot as servants of the Demons. After these are released and returned to the kingdom by the Seven Deadly Sins.
When the Holy War against the Demon Clan finally takes place, Liones forms an alliance with the Four Archangels to be part of Stigma and fight against the demons. Liones becomes the headquarters of the allied forces. When the forces are divided for the confrontation, a group of Holy Knights, the Defensive Force, is designated to protect the kingdom in each entrance.
- Liones is named after Lyonesse, a country in the Arthurian legends which is the home of Tristan.
- Before its destruction, Danafor was the only country who could rival Liones in terms of power. Although, prior to its destruction as well, Camelot was believed to be a growing power that could potentially surpass Liones.
- Liones has a national holiday called the Kingdom Founding Day, which was also the day the Seven Deadly Sins were framed as traitors.
- Liones has been ruled by twelve kings, including Bartra and, currently, Meliodas.