Its major historic error to make Franks united in 480 AD, as Franks were divided to Salian Franks and Ripuarian Franks, when Clovis was King of Salian Franks and had alliance with Ripuarian Frank who assisted with his invasion of Neustria. Bit later Ripuarian Franks were led by Sigobert the Lame when his own son murdered him, Clovis killed Sigobert's son and became first King of the Franks.
Its also big issue that Roman Empire is called "Byzantium" in 480 AD. In vanilla I can accept the silly ahistorical name that nobody ever called it , but in 5th century... Just to make it it clear:
*Even before WRE fall, ERE was already counted as senior empire.
*Odoacer sent crown of WRE to ERE emperor.
*Emperors spoke Latin (as Justinian the Great was the last Latin speaking emperor).