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Barbarian
Tough, big, powerful

• Has skills like Battle Rage, which increases damage 100%, and Iron Skin, increases his/her armor by 20%, and a slew of other melee-based skills
• Can dual wield weapons
• Makes a perfect tank
• Wasn't too different than the Barbarian from D2, although it sure looks a heck of a lot better, so we didn't spend too much time with the big brute. Still, when you just need someone to kick ass, you can't go wrong with this one.

Witch Doctor

• Incredibly creepy and cool, and has a nifty Cajun dialect
• Extremely fun and imaginative spells like Zombie Wall, where a wall of undead rise from the ground and both blocks and attacks your enemies.
• Uses toads, locusts, and even spiders to swarm and vivisect enemies
• The Skull of Flame spell makes an excellent ranged attack, and does area damage. Plus, it just looks cool. In the videos they showed us (but not in the demo), when you slot the Multistrike Rune in this spell, the skull bounces, and does big area damage with each bounce.

Wizard

• The Wizard was the only class that had the Rune system working, and we put it to extensive use. It truly changes your spell, and you'll be mixing and matching a lot.
• Make sure you select Disintegrate early on, because it's an extremely powerful spell. Your character locks in place while you hold down the mouse button, and you mouse around in circles to aim at your enemies and melt them.
• Can use items like Wands and Orbs
• Has melee and ranged spells