I was surprised to learn that submerging in the water cured people. My rational brain explains it by claiming it is the parasite worms need to breath that ends up as their death. What I don't get is why the worms don't die from blood, but from water. Any water. So, why is that blood, which is part of water, doesn't do the same thing?
Is there something in blood that enables the parasites to live? The whole necromorphosis has problem areas. A logical pitfalls. Stuff that doesn't make much of sense, but can be ignored if you turn off your sense of disbelief. If you do that, a wonderful show emerges. Then there is the other thing, the princess. We know that she willingly let the dead to consume her, and she was showed having extensive wounds when she charged to the reservoir and got trapped in the good stuff.
The most interesting part is that she escaped her death, was never recovered and then she went to North to turn whole thing around. Maybe the absolute best part is that she found a way to make the dead even more frightening than before by simply attaching bells to the dead. What a marvellous idea.
Well done. So, let's say she conquers the south and then move to China. There is nothing they can do to in China to stop the avalanche. The only way to stop them is a moat, and if the princess figures out to coat her dead with mud, that might not work either, making the states and the islands the only places to be able to escape the apocalypse. Then they only need to stick around forty years for the princess to die of old age, and things can be turned around.
Except in the land of the fantasy the dead live forever, because reasons.