I wanna touch back on my little theory that the human reaper is what will be there next form as they use species from their cycles to renew themselves into new bodies...I was listening to what Harbinger said at the end of Mass Effect 2...
Your species will be raised to a new existence
We Are The Harbinger Of Your Perfection
You will surrender your potential against the growing void
We will bring your species into harmony with our own
We are the beginning you are the end
Seems pretty clear to me we are going to be used as the next evolution of the reaper, which makes ME2 ending a lot better IMO.