User blog comment:Markurion/Extended Cut or Prolonged torture?/@comment-3304657-20120411210950/@comment-5017885-20120414065354

It was Harbinger. I believe Anderson's the one who mentions that Harbinger and a group of Reapers broke off from the battle in orbit, and if I recall, there's even a cinematic of it. That said, Harbinger also has a unique appearance; no other Reaper has his "yellow eyes", with all others being Destroyers or Sovereign look-alikes.