Assassin****

The Assassin walks the shadows, a deadly viper ready to strike at the heart when the enemy least expects it, nowhere and everywhere all at once. Assassins are masters of their chosen weapon, the dagger, and are expert at inflicting Critical Strikes to their enemy's weak points causing massive damage.

The Assassin is trained to efficiently link attacks together in a chain that does not give the enemy a chance to hit back. They have mastered the ability to move as shadows—Assassins wear only lightweight armour and prefer to avoid damage by not being there when the enemy's strike lands. Their other magical skills include Hexes that lower the target's defences and protect the Assassin from harm.
http://eu.guildwars.com/gameplay/article/assassin/