Fantasy New World and the Romans

In 1653 AD, under the blessing of the Greek gods, the New Roman Empire on the east coast of North America had entered its second century. The defeated elven invasion two hundred years ago became history. A millennium belonging to the Hellenistic kingdoms on the east coast had passed. The polytheistic empire left by "Emperor" Constantine XI became the overlord of the New World. The Vinland Kingdom of the Old Gods in the North is a loyal ally of New Rome. The pagan colonists of the Old World are blocked in the swamps and the end of the peninsula in the south. The mysterious merchants of the Aztecs haunt the harbor... Across the stretching New Olympus Mountains, to the west beyond the border provinces, the expansion of the elves killing plains orcs came to an end, and the dwarves from afar also brought silk and porcelain from the west coast... But now, Isaac, the time traveler, just wants to know: In this seemingly DND-style fantasy earth, why did the goblin chief turn into a purple-black giant living bead that could play with a dragon cart in front of him? !