Offa (died 796) was the King of Mercia, reigning from 757 until his death. His rapid expansion of his territory paved the way for the unification of England, and he was considered the most powerful Anglo-Saxon king before Alfred the Great. Unbeknowst to many, Offa was also a member of the Order of the Ancients.
Offa built a linear military fortification to define the western border of Mecia.  Later, this fortification was named after Offa, and it was called Offa's Dyke. Under Offa, the rule and prosperity of Mercia reached its peak. Offa also detailed the previous kings of Lindsey, which survived in the Anglican Chronicle of Kings. These kings claimed to be the descendants of the god Woden. He also built a fort in the Cyne Belle Castle as a proof of the superiority of Mercia.
Offa's membership in the Order was eventually uncovered by Tata, a Palatinus of the Order whose grandfather fought alongside Offa. Tata later learned all he could of Offa and sought to follow in his footsteps.
- Assassin's Creed: Valhalla (mentioned only)