Harbinger comes with a message:  The Apocalypse is coming.  He is angered at the other wrestlers - the modern-day "warrior hero's" in his mind - battle over petty belts while ignoring the upcoming doom which awaits us all.  The USXWF is his means of gaining recognition, so he may easier spread his warning of the imminent destruction of humanity.

Pulling Harbinger's strings is the Gatekeeper... he was the one who found an amnesiac Harbinger and recruited him as a "minion of the darkness".  Few take these two seriously, although the conviction in Harbinger's and Gatekeeper's words and actions is evidence enough that they have no doubts about their accuracy.

When he enters the ring, Harbinger makes his presence felt.  He's capable of such feats of strength, it often appears superhuman.  Once he gains the upper hand in a match, he rarely loses it.  His sheer strength usually allows him to keep his opponent's down, and his stamina lets him take a licking and keep on ticking.  This ravaging wrestling style is improved by his sheer ferocity in handling opponent's... he and Gatekeeper are hardly above permanently damaging a fellow wrestler.