Ichigo is a mixture of every creature shown in this manga from the beginning (just us fans didn't know about it). It was explained in the "Everything but the rain" chapters: Masaki got attacked by Aizen's little pet experiment and was about to turn into a hollow. Then Isshin, with Urahara's help, became her opposite (sninigami in a "human"body) to balance her out and save her. So Ichigo gets the hollow and the quicy from his mom, and the shinigami and the human from his dad.
To Kumiko-chan:
Ichigo is a mixture of every creature shown in this manga from the beginning (just us fans didn't know about it). It was explained in the "Everything but the rain" chapters:
Masaki got attacked by Aizen's little pet experiment and was about to turn into a hollow. Then Isshin, with Urahara's help, became her opposite (sninigami in a "human"body) to balance her out and save her.
So Ichigo gets the hollow and the quicy from his mom, and the shinigami and the human from his dad.