Speak of the Devil, and he shall appear. The Harbinger drops down behind your group. It opens it maw, tentacles writhing in the back of its throat; and lets out a bloodcurdling mixture of a screech and a roar. Hearing the Plague masses surging through the station's wreckage, it turns and lets out a demonic laugh. It begins to walk toward you. You can either GTFO of there or try and fight it back; your choice.