The Crusader class is a new class that will be added in the Reaper of Souls expansion.
He is, in effect, a Paladin from the Kingdom of Westmarch.
As quoted by Games.on.net, a visitor to Gamescon:
“Malthael, the Angel of Death, intends to end the eternal conflict between angels and demons by wrapping up all of humanity to deal with the human problem,” intones Kevin Martens, lead designer of Diablo 3 expansion Reaper of Souls.
“Frankly, he’s frightened by the amount of power that the player has gotten now that they’ve defeated the Prime Evil.”
After seeing the new Crusader class in action, I have to say that Malthael is right to be concerned. This guy is a beast.
Powered by Holy Wrath and armed with a heavy shield and flail, he’s a mid-range melee character whose most powerful attacks are reserved for close-quarters but he also sports a number of ranged options. In Martens words he’s a “War machine made human; a modern tank made in the form of medieval warrior”. Indeed, he’s so aggressive that even his Crusader shield can be wielded offensively.