Serecio was a Great Being and a member of the Council of Great Beings. He had an army of Rahi and flying robots.
Serecio was among the Great Beings who were summoned to a meeting of the Council, during which Angonce and Uterio di Armechio proposed to start a war against Blackout. After initially questioning whether Blackout was a threat, Serecio chose to side with the GBs who decided to go to war against Blackout. He and TPK briefly fought, and TPK and Luigi then left the chamber. Angonce declared war.
Serecio then gathered his armies, and gave half of them to Rahksha.
During the Battle of Krustallos, Serecio ordered some of his troops to attack enemy ships with Blade Dragons. After User Kon was teleported to Makuhero City, Serecio went into a trance. Eventually, he woke up, and ordered his troops around during the Battle of Malchior IV. He was then told to withdraw them by Angonce, as Uterio was planning on using a "specific weapon". He did so, and then left. He then attacked Alaine, where The Shima Brothers attacked him. After that, his ship was heavily damaged by a battle between Strike Destiny and Wing Justice. The ship crash-landed, and was forced to make repairs on the planet.
When The Visitor appeared and took Yon from the clutches of Serecio's henchmen, Serecio was not pleased, and unleashed the Rahi. He then contacted Uterio and asked what he should do about the Visitor.
The Toa Yerta then appeared on his ship, and Serecio blasted them all through a wall.
Serecio was then summoned to a Council meeting by Angonce, along with many more GBs. During the meeting, he and TPK argued a lot, and Serecio was backed into a corner by TPK's arguments. He then voted for Angonce's proposal to indiscriminately kill all combatants in the Uterio War, and TPK commenced Operation Dakar, his attempt to take leadership of the Great Beings by force. Serecio teleported away, but was ambushed by Barricade and Bonecrusher. After defeating them, Serecio teleported away again.
At some point, Serecio was given the Orb of Summoning by Quolas, and used it to summon The Guy Who Was Engulfed In Milk, Iron Man, Kranxx, the Savant, Kremika and the Caged Addict. Serecio then told Quolas that, in the event of his death, Quolas was to take his place on the Council.
Serecio then lead his new troops in the Battle of Mordor. TPK then appeared and attacked them, and Serecio responded by jumping to the ground and blowing up TPK's stolen Skyboard. The two then fought, and TPK defeated Serecio. Despite his plea, TPK then shot him with his rust gun four times, killing him.