The pack includes two new characters - the Necomancer (natch) and the Cult Minion. There will also be a new Animal Orb - the Dragonhead, and two weapons: the NG Skull Mace and the chainsaw.
"Yes, ... the damn Chainsaw," writes Kelly for The Behemoth.
"We will post the date as soon as we find out!" Kelly adds. That goes for the price, too. "Once again, this is completely up to Microsoft. But I can leave you with a tantalizing ... SOON."
Necromantic Pack DLC [The Behemoth, via Joystiq]