Ichigo the Nephilim
One interpretation of the Nephilim is that they are the offspring of an angel and a human. And in some cases, they are considered as a bad omen. In pop culture, they are even considered to be the cause of doomsday.
The Shinigami is probably the closest we can get to a Bleach version of an angel. Ironic, considering that they translate into Grim Reaper in the West. And although they lack the ability to do divine and miracle works, they still have the ability to purify souls and usher them to Soul Society.
As for the Quincy, though they have the ability to manipulate reishi, they are still considered human.
Ichigo from the very start always wanted a normal life. But he nevertheless finds himself in the middle of two opposing forces. And while he does have immense power, he is still a teenager and didn't have decades of experience mastering it compared to other equally powerful characters.
And what's more intriguing is that Aizen had a hand in Isshin and Masaki's first meeting. And to reinforce my previous blog about his similarities with Lucifer, it's as if he helped create a Nephilim - an omen for things to come.