User blog comment:Diyartifact/Shepard's adversaries/@comment-1895174-20120408234519

Harbinger is NOT the primary antagonist of Mass Effect 2. An antagonist, yes, but not the main one. In fact, Mass Effect 2 is a game without a central primary antagonist, as the Collectors as a whole take on that role. Although it's rather obvious, there is no clear indication throughout ME2 until the very end (barring DLC) that Harbinger is a different character, much less a Reaper. Like Sovereign in ME1, he's not the Big Bad, just the Puppet Master.

If anything, the enemies we face in ME3 are a combination of the enemies we face in the first two games. Cerberus is like the geth, being commanded by an oft-seen leader who, for what it's worth, both show clear cybernetic implants, refuse to believe they are indoctrinated, and kill themselves once they realize they are. The Reaper ground forces are also a clear parallel to the Collectors, especially once you consider the Collectors are just Prothean husks.