Nations are immortal. You can stab them, shoot them, poison and behead them. They will get back up and walk it off. The only thing that 'kills' them is collapse or revolution. They crack and turn to dust and then just reappear in Pangaea. Pangaea is a sort of pocket dimension parallel to our own. Nations and select humans can easily cross back and forth. When a nation 'dies' they cannot leave Pangaea until they have completed x number of years. How long until they can leave depends on how long they presided over their country. Soviet Union has to stay in Pangaea for 69 years before he can leave. Russian Empire has to stay for 196 years. Third Reich had to stay for 12. Soviet and RE cannot currently leave but Reich can and this annoys them and many others immensely.
Retired nations also have their own world meetings modeled after the current nations ones. They don't really do anything useful and mostly just fight each other. Don't you dare try to take away their meetings though or say they are unproductive. They will fight tooth and nail to keep them, even if they hate them.
Many nations often go into steep mental or physical decline. If you thought Third was crazy before he 'died' wait until you meet him now. Although most of the nations who have declined already had issues before their 'death'.
The nations all have had some kind of moral decline. Even the most rational, kindest nations, have more or less become sadist assholes. Ancient Greece would love to chat with you, just be wary of the fact that she will stab you for no reason.
