Very interesting stuff. This is the first time I've seen a Harry-son-of-Bellatrix story that's actually believably pulled off. You've turned Harry into a powerhouse of the right sort, not overly powerful, yet not weak by any means.
Bellatrix is interesting, too... I guess the logic you're going by to justify her hurt-not-kill attitude is that since she didn't go to Azkaban, she doesn't have some insane proclivity towards killing?
Either way, excellent stuff, and good luck updating.
Author's response
I've taken some liberties with canon's Bellatrix, and I don't think that my Bella would become insanely sadistic if sent to Azkaban. Her hurt-not-kill attitude is simple pragmatism, she has no qualms about killing Death Eaters.