The Four Noble Clans

[Death BOO Z]

I think it's possible that she was a shinigami, or at least had enoug spirit energy to satisfy grand fisher's appetite.
maybe Isshin had to quit becuase he married a lower-class woman?

[ruccus]

That's really the conclusion I'm coming to through this topic as well because really she can't just be a normal human. I don't believe Isshin, possibly a captain, would marry a regular human, even if she had high spiritual energy. But one thing we can all (hopefully) agree on is that Ichigo's mother is not a regular human.

[Chiodos]

I think it's possible that she was a shinigami, or at least had enoug spirit energy to satisfy grand fisher's appetite.
maybe Isshin had to quit becuase he married a lower-class woman?

Quite nice Theory. He found an lower class women. Maybe way down the scale, want to be, like..forever with her and with a little help of Urahaha, they all escape from Soul Society?