I read that, a long time ago. It was good, but I got weighed down later in the series. I think I got to book four before giving up.

I don't know if HP will kill out of love. That might be a bit deep for what is still ostensibly a kid's novel. But he cannot kill purely out of hatred - it has to be done cleanly, a job that must be accomplished, not a revenge thing so much as shoot-the-rabid-dog.