Here is a list of other empires related to Rome. I may add the non-Roman ones later, but for now, here they are
The Byzantine Empire was formed when the Jewish Roman general Josiah basically marches west to Byzantium and takes it, in the process breaking away from the Ophite Empire Eventually the Ophite Empire is reconquered. The Byzantines go on to found colonies in the New World the same time as Rome. They refuse to reunite until the Mongols invade. Thankfully, nnovative defenses would help save the empire. After the last ruler, Tarterus died, the Byzantine Empire officially rejoined the Romans, as evidenced by the marriage of Tarterus's youungest daughter to the heir to the Roman throne.
The Ophite Empire would be formed in response to the brutal and insane actions of the tyrannical emperor Andronicus by the slave Ophius in Mespotamia in the year 1108(1861 AUE) After the Romans threw the Chinese out of India in 1113 CE(1866 AUE) Ophius was able to conclude peace with the Romans in exchange for independence by 1867 AUE. It would be around for maybe 40 years before the Byzantines took it over.
This empire-in-exile was formed by the legitimate Roman emeperor Polyphemus around the time he was 18 in response to Palpitus' illegal declartion of himself as emperor. Sarmatia, Germnaia, and Scandia would break away while Polyphemus cocnentrated on trying to overthrow Palpitus. Though Palpitus would be killed in a battle in Egypt, thr two empires would not officially reunite until a couple of years later under Poyphemus' son.
The Empire of Yenchi can best be described as a heavily Roman influenced state of mixed Sino-Turkic origin. It first broke away from China as a republic when China regained it's independence from Rome. Though China would reconquer it, it would regain indepdence after the Mongols' massive invasion.