Arbus is a priest who joined the Great Fight Festival for unknown purposes.

Melodias, Hawk, and Elizabeth retook the Kingdom of Leones from the Holy Knights. The festival went off without a hitch and the crew enjoyed their well-earned peace. And yet, another threat looms on the horizon. The Ten Commandments, a group of elite demon clan warriors, have their sights set on the kingdom.
 
(Source: Anime News Network)

Despite repelling the demon invasion of the Kingdom of Lioness, the war is far from over, for Arthur's Kingdom of Camelot is still being occupied by the demon army and the surviving members of Jikkai. However, in order to begin counter-offensive, the Seven Deadly Sins needs all of its members. Unfortunately, King and Diane are still hiding in the Fairy King's Forest, where they are made to discover the strange history of Jikkai.

When they were accused of trying to overthrow the monarchy, the feared warriors the Seven Deadly Sins were sent into exile. Princess Elizabeth discovers the truth the Sins were framed by the king's guard, the Holy Knights too late to prevent them from assassinating her father and seizing the throne! Now the princess is on the run, seeking the Sins to help her reclaim the kingdom. But the first Sin she meets, Meliodas, is a little innkeeper with a talking pig. He doesn't even have a real sword! Have the legends of the Sins' strength been exaggerated...?
 
(Source: Kodansha USA)
 
Note: Chapter count includes 346 regular chapters, 18 extra chapters, and 3 gaiden chapters.