Depends, who are you rebelling against? This could spark the Second Celestial War, in the middle of a famine and disease ridden time. Will be very interesting :3
It wouldn't really spark a second Celestial War, because how would he get a lot of troops? Nations are fighting and working on problems with diseases rn.
No just Acrea, but also Rhun. It's possible for Assassin to do so, since his people remained in the same place, but it would be harder for you, Death. Your entire population was almost comepletely destroyed