My writing group talked about how readers identify with characters last night, and one member commented that people are most likely to identify with characters who are like themselves. They were referring primarily to characteristics like race and gender. Although there is truth in that statement, I don't have trouble myself identifying with characters who are quite different from me in those aspects. In reading SF/fantasy and horror I've identified with plenty of characters who weren't even human. I mentioned a book here a few days ago by David Gemmell called Winter Warriors. The book has an ensemble cast but my favorite character is the lone black swordsman in the tale. I identify strongly with him.
One the other hand, I recently read a book by the African American writer Donald Goines called Inner City Hoodlum, and I couldn't identify with any of the black characters (or white ones, for that matter) in that book. This got me to thinking, why could I identify with a black character in one case and not another? I think there are two reasons.
First, the main black character in "Hoodlum" has ambitions that I don't share. He wants to get rich, wear fancy clothes, drive a fancy car, and have sex with a new woman every night. In other words, he was not like me at all on the inside. Nogusta, on the other hand, the black swordsman from Winter Warriors, wants a quiet place of his own but has duties that keep him from getting it. He cares about other people (perhaps more than I do), and is hard working, loyal to his friends, and misses his family. Boom, identification.
Second, Nogusta's goals in the context of the book are universal ones. He's not in it to help just himself or those who are replicas of himself. He wants to make the world a better place for everyone. He wants to see "all" children happy. He even cares about animals, and rescues a horse from slaughter because--even though it is old--it has a noble and brave past.
Putting aside any discussion of "realism" in characters, Nogusta is the kind of person I'd like to be. Any character, of any race or gender, or species, that shows these kinds of universal goals will be someone I can identify with.