The Announcer

"Oh! Hello there, Welcome to Hades.  I'm your spirit guide..." "Do you find me irritating? Well, at least I'm not trying to put HOLES in you!"

-The announcer

The announcer is your one and only friend in the game (Besides your... "friends"), and will help you by making fun of you when you die, stating out the obvious, and giving you information about why you're dead, but he's most likely lying about that anyways, Basically he's just there to be a prick..

Involvement
As said above, he's there to be an annoyance. But as he said, he's not trying to kill you. There is a possibility that he's helping the demons kill you, though. Plot-wise, it is unknown whether or not he is a god, assistant to a god, or maybe lucifer himself. For all the player knows, he could be the hatred inside of you, boiling up til you just pop. Or maybe he's just some fat guy in the sky, we have no idea, the point is he's there, and you gotta do what he says, or else... well, 'm not too sure, actually...

Personality
Despite being your only friend, he takes great joy in watching the player's fight and die, almost to a cynical level. That's really all that can be said about him...

Trivia

 * He's loved amongst the players
 * His voice is amazing
 * Nobody know's anything about them, and nobody will probably ever know.