User blog comment:Diyartifact/Shepard's adversaries/@comment-1895174-20120408234519/@comment-1895174-20120410035301

I recognize that every fight with the Collectors is in effect a fight with Harbinger, but I'd still argue that doesn't necessarily make Harbinger the primary antagonist, mainly due to his limited presence. The primary antagonist is the character that, from early in the game, we want to fight at the end. We don't even know that Harbinger is a separate character from the Collector General until the Human-Reaper is destroyed. We seem to forget that was supposed to be a reveal. An obvious reveal, but a reveal nonetheless.

Let me put this question out there for OP, Markurion, and Aleks: Using the same logic you are using to prove to me that Harbinger is the primary antagonist of Mass Effect 2, why then is he not the primary antagonist of Mass Effect 3 as well, or at least shares the role with the Illusive Man?

We see in Arrival that Harbinger signals the invasion, and details in 3 reveal that he is the largest and oldest Reaper in the fleet and leads the Reaper invasion of Earth. He personally attacks Shepard at the end of the game. Therefore, it is implied from the end of ME2 through ME3 that Harbinger is the (for lack of a better term) alpha Reaper second only to the Catalyst (which I think we can all agree is a part of the game we'd like to forget).