I started with the question: why did Voldemort survive when hit by the rebounded Killing Curse, whereas Nagini and the other Horcruxes were destroyed when their containers were? We know that the destruction of one Horcrux doesn't affect the others, including Voldemort himself, so why did his soul persist? In my opinion, Voldemort essentially made himself a Horcrux too. By splitting his soul into fragments, his own body may have been treated like a Horcrux vessel, which would explain why he couldn't sense the other fragments as they were destroyed—because his soul was divided and disconnected from the whole leading to my want to make a story exploring this.