EatChildren
Currently polling second in Australia's federal election (first in the Gold Coast), this feral may one day be your Bogan King.
Well, the Leviathan explanation of a Reaper's purpose makes loads more sense. This should have been the MacGuffin.
BioWare's strategy with this game has been all kinds of fucked up.
I still think it's stupid in the context of the way you've interacted with Reapers in the past (eg: dialogue with Sovereign), but it's something in the face of nothing, and that something is believable and understandable in the context of Mass Effect 3's plot arc.
For those who want to know know how Leviathan explains the Reapers:
the Leviathans were the first dominant species in the galaxy. Every other species was subservient, worshipping the Leviathans as essentially gods. As these species evolved, they eventually created machines that would wipe them out. The Leviathans got tired of trying to micromanage dumb species constantly wiping themselves out, and instead developed a babysitter AI (the Catalyst) to watch over the numerous species of the galaxy. The AI's goal was simple to ensure organic life was preserved.
The AI experimented with solutions to this 'problem', such as guiding organic species along a 'safe' controlled technological path (relays, and so on), but for whatever reason deemed preservation of organic material through 'harvesting' into great singular creatures was the best solution under given circumstances. The first species 'harvested' were the Leviathans, and thus was created Harbinger, the first of the Reapers.
Ever since the original harvest the Catalyst has been using the galaxy as an experimental test bed to find a better solution to the 'problem' of organic preservation, using Harbinger to lead the charge and harvest sentient species in the galaxy for reasons. This is why the cycle is stuck in a continuous loop: as part of it's original programming, the Catalyst is looking for a 'solution' as organic preservation, and it calculates harvests/Reapers is the best it has.
The AI experimented with solutions to this 'problem', such as guiding organic species along a 'safe' controlled technological path (relays, and so on), but for whatever reason deemed preservation of organic material through 'harvesting' into great singular creatures was the best solution under given circumstances. The first species 'harvested' were the Leviathans, and thus was created Harbinger, the first of the Reapers.
Ever since the original harvest the Catalyst has been using the galaxy as an experimental test bed to find a better solution to the 'problem' of organic preservation, using Harbinger to lead the charge and harvest sentient species in the galaxy for reasons. This is why the cycle is stuck in a continuous loop: as part of it's original programming, the Catalyst is looking for a 'solution' as organic preservation, and it calculates harvests/Reapers is the best it has.
As said though, this still doesn't excuse the heinously stupid end game 'solution' to the 'problem', the 'problem' that doesn't actually exist and instead contradicts everything you know. Leviathan puts more pieces of the puzzle together but the end picture is still a big turd.