Well, in bleach, most people would ask, what the hell happens to the souls that die. Well, thats easy; they are reincarnated.
My theory: see Senna. When her spirit died and passed on, she was turned into a little girl. of course, she didn't know Ichigo, but that was her.
Another theory: Rukia constantly acknowledged how Ichigo looed like Kaien Shiba. Kaien died MANY years before Ichigo was born, and as a result; was reincarnated as Ichigo Kurosaki.
Proof: Aaroniero Arruerie, the 9th Esapda, PRETENDED to be Kaien. Aaroniero takes the persons bodies, memories, feelings, voice, and appearance and "becomes" that person... but Kaien's spirit died long ago, and his body was used by Aaroniero.
My theory: see Senna. When her spirit died and passed on, she was turned into a little girl. of course, she didn't know Ichigo, but that was her.
Another theory: Rukia constantly acknowledged how Ichigo looed like Kaien Shiba. Kaien died MANY years before Ichigo was born, and as a result; was reincarnated as Ichigo Kurosaki.
Proof: Aaroniero Arruerie, the 9th Esapda, PRETENDED to be Kaien. Aaroniero takes the persons bodies, memories, feelings, voice, and appearance and "becomes" that person... but Kaien's spirit died long ago, and his body was used by Aaroniero.