Joining the Danes
Allegedly a member of a branch of the Iclingas dynasty that ruled Mercia, Ceolwulf was originally a nobleman who served in the court of King Burgred during the early Viking expansions into England. As the Anglo-Saxons suffered numerous defeats to the Vikings, Ceolwulf, like many noblemen, defected from the king's side and looked to make the best of disadvantages brought on by the wars. Ceolwulf decided to ally with the Sons of Ragnar, Ivarr and Ubba Ragnarsson and proposed a deal to make him king which he hoped could spare his kingdom from the ravaging war. His son Ceolbert later became under the tutelage of Ivarr.
Some time after King Burgred paid off the Vikings to prevent war, the Sons of Ragnar returned to Mercia to take the kingdom with themselves. In 873, Ceolwulf met with the brothers and Sigurd Styrbjornsson in Repton to discuss an assault on Burgred's stronghold in Tamworth. As they were joined by Sigurd's sister Eivor Varinsdottir, Ceolwulf insisted that the stronghold be taken with Burgred' alive. When Eivor questioned his alliegance due to his betrayal of his former king, Ceolwulf remarked that he only wanted what he wished was the best for his son and the kingdom. Later on, Ceolbert joined the Vikings in journeying to the war camp in preparation for a siege on Burgred's stronghold.
Behind the scenes
Ceolwulf II is a historical figure and character appearing in Assassin's Creed: Valhalla, narrative director Darby McDevitt revealed on Twitter that the voice of Ceolwulf was provided by Mark Bonnar.