Not sure I agree about the unforgivables though. Why would a healer invent a spell that not only kills, but is also completely _unblockable_ by any means.
Why would a healer design a torture spell that could permanently destroy your brain if maintained long enough. Magic could easily restart hearts and such without that.
And if you can hit someone with imperius you can also hit them with some paralyzing spell or such that would render the person almost equally harmless.
I can agree that dark magic can be used for good, even the unforgivable spells but I think you went overboard a little here with having the most effective way to kill be invented by a healer. Would have made more sense in my opinion, to have the spells be invented by a dark wizard but still have Harry find a good use for them.
The whole thing with Ginny was unexpected. In canon the diary wanted to drain her of her life in order to become physical. Why would that have changed merely because Harry was not present. Hopefully you have a good explanation about this. Also why is it that Harry let Ginny run away to hide the diary or whatever. Should he not have stunned her and retrieved the diary while he still could. He has also revealed himself to Tom now so he can probably expect a basilisk to drop in for a visit. This whole thing made little sense to me?
Other than those "nitpicks" I liked this chapter (as usual). The whole thing with Luna was especially sweet. :)
Ah, why would a healer invent a spell that only kills? The Guillotine was invented by a doctor who wanted executions to be more merciful and quick. Dr. Kevorkian has invented a number of machines that would allow terminally ill patients the ability to end heir lives on their own terms. Throughout history, healers have seen that sometimes death is a mercy. As for it being "unblockable", is morphine blockable? Or antibiotics? Why would blocking the effect of a treatment, and in this case death is a form of treatment, be part of it's development? Even if the AK was designed as a weapon, do one develops a weapon with the idea that it can be rendered ineffective, trust me I know about this.
As for the Imperious, in the example given, any spell that physically impacted the target would run the risk of causing unexpected and unpredictable movement which would result in the hostage being injured, and with a poisoned knife that means killed. Thus a non-physical means of resolving the situation is needed. Please note that I never said that this is how or why the Imperious was developed, only a possible use of it.
The point of the entire discussion was to show that labels such as Dark or Light, good or evil are not truly applicable to non-sentient things. Only the user of the tool can be judged not the tool itself.
I'm glad you were not expecting the interchange with Ginny. For a hint of what happened between Ginny and Tom in this universe, reread the part of CoS where Harry first finds the diary and then imagine a slightly different set of circumstances.
Thanks for a thought provoking review and I'm glad you enjoyed the story so far.