Which modern country is the successor of the Roman Empire?

[TheReckoning]

The last Roman successor state in the West (the Kingdom of Gwynedd: its boundaries always shifted about, but it covered most of North Wales most of the time) fell in 1283 and the last Roman successor state in the East (the Duchy of the Archipelago: essentially the Cyclades) fell in 1579. Some people would not count the Duchy of the Archipelago as it was created by Venetian adventurers/pirates during the general chaos following the Fourth Crusade, in which case the answer would be the Principality of Theodoro (a tiny Gothic-speaking slice of southern Crimea that was nominally attached to the equally tiny Empire of Trebizond) which fell in 1475. None of these places were fully sovereign all of the time by a modern understanding of the term, but that's not really important: what matters is that they were all clearly defined polities. Anyway, there's nothing afterwards.

HRE could be considered a revival of the Western Roman Empire, just as the Russian Federation could be considered a revival of the Russian Empire, in my eyes.

[TheReckoning]

The last Roman successor state in the West (the Kingdom of Gwynedd: its boundaries always shifted about, but it covered most of North Wales most of the time) fell in 1283 and the last Roman successor state in the East (the Duchy of the Archipelago: essentially the Cyclades) fell in 1579. Some people would not count the Duchy of the Archipelago as it was created by Venetian adventurers/pirates during the general chaos following the Fourth Crusade, in which case the answer would be the Principality of Theodoro (a tiny Gothic-speaking slice of southern Crimea that was nominally attached to the equally tiny Empire of Trebizond) which fell in 1475. None of these places were fully sovereign all of the time by a modern understanding of the term, but that's not really important: what matters is that they were all clearly defined polities. Anyway, there's nothing afterwards.

HRE could be considered a revival of the Western Roman Empire, just as the Russian Federation could be considered a revival of the Russian Empire, in my eyes.

I was going to make a comment joking about how the answer is clearly Germany because of the HRE -> Confederation of the Rhine -> North German Confederation -> Germany succession, but it’s less funny when there’s people in thread actually claiming that the HRE was a successor of the Roman Empire.

It used the Roman language, practiced the Roman religion, and was considered to be Roman by the people who lived in and around it. That doesn’t mean it has to be a successor state, but I could see an interpretation of the terms “successor state” and of historical analysis at the time to determine that maybe it was.