User blog comment:Berserkchart486/Warring States Fanon Canon/@comment-6673974-20141225023253/@comment-6003865-20141225072446

If you really want to get into it, spacetime should be almost completely gone, and unless you are in a clan that specializes in fuinjutsu, aka the uzumaki, only the absolute basics should still around. Even then, your fuinjutsu should likely be weaker than theirs, cause they had a thousand years to get to that point. Simple fact of the matter, people would die too fast, and be too focused on survival, to create a technique that requires that long to develop.