Surprised when he asked that. Did he not know that was his form of immortality? "Yes, Horcruxes. Like phylacteries for liches. Technically if someone kills however many Horcruxes a person makes, the person is vulnerable to be permanently killed." Voldemort was a truly greedy man by creating multiple Horcruxes. I had no idea how many, but creating more than one was idiotic. It was possible that he was going for one of the power numbers in arithmancy to solidify his immortality. 