Take a look to this presentation videos of the four classes of Diablo IIIHere are four presentation videos of the first heroes from Diablo III.
In them you will find the Barbarian, the Demon Hunter, the Witch Doctor and the Monk .
The barbarians. Mighty warriors whose strength and ferocity are a match for any foe, whether slavering beast or foul demon. Tall, broad, and rippling with muscle, the barbarian can bear a heavy weapon too large for a commoner to lift, or wield two full-sized armamentsone in each handwith wickedly lethal purpose. In the wild and monstrous lands of Sanctuary, there is nothing more frightening than a barbarian with a dry blade.
The demon hunters. Vengeful harbingers of righteous doom who bring swift judgment and death to the hellish creatures daring enough to trespass on the mortal lands of Sanctuary. Skilled archers, assassins, and trackers, demon hunters are perfectly honed instruments set to scour demons from the world. The fact that every last one of them has a deep and personal motivation to do so only sharpens their deadly purpose.
The witch doctors. Sage conjurers, enchanters, and mystical warriors who are driven by a charge to maintain spiritual balance and harmony in the violent world of Sanctuary. They command ancient magics rooted in the primal powers of life and death, and are adept at summoning fearsome, shadowy creatures. A witch doctor is armed with simple talismans, fetishes, rough carvings... and endless ravening throngs of vengeful spirits set to bring destruction at their master's command.
The monks. Holy warriors who believe that the madness and chaos of Sanctuary are destined to be brought into order, and that it is their sacred mission to assist their thousand and one gods in doing so. Arrayed in the fiery colors of Ytar, the fire god, monks draw from their years of intense training and meditation to become masters of melee combat. While proficient with many types of weapons Aistaves, blades, maces and spears, monks have no real need for such crude tools. Their discipline has honed both body and mind into living instruments of divine justice.