I was talking with a friend about this and we got to thinking about the power that was wrapped up in the CI bloodline curse. There was a LOT of power in it.

Consider that we first saw this spell in Storm Front where a 2-bit hack like Victor Sells could use a regular thunderstorm to power a spell capable of ripping the hearts out of two people - 1 the target, one just in proximity. Now, the CI bloodline curse was magnitudes more powerful. If Sells' spell was a match, the CI spell was a whole compliment of a Triden Missile Submarine ICBMs. WAY more than would be necessary to fry Harry. Way more than would be necessary to fry Eb (even with the Blackstaff - which doesn;t seem to make him immune to magic - it just shields him from negative influences). So who up the line from Eb (or Maggie Sr.) was the real target? And how come that person needed so many human sacrifices to power the spell, plus days of rituals, plus the collected power of the Lords of Outer Night, plus the Red King, plus the inherant power of CI itself, etc. The end result was the instant genocide of the Red Court - a large collection of powerful, near immortals. Something was in the Red Court's crosshairs that needed that much power.

OR

Could the RC have been duped into overpowering the spell to such a ridiculous degree as a way of ensuring it was powerful enough to wipe out the Red Court itself, and Harry was maneuvered into making the decision to make Susan turn and then murder her to eliminate the Red Court using their own spell? We have seen a few beings who could engineer something like this. Mab and Uriel spring to mind immediately. We have also heard Nic say that the Red Court was a problem that would be disastrous to his long term plans.

So - who was the target? Or who loaded the gun for the Red Court and got Harry to pull the trigger on their own assisted suicide?