Divine Aura

The Divine Aura is a bonus that comes with the Collector's Edition of Guild Wars. It only comes with the Collector's Edition; there is no way to "unlock" it, as some believe. The Collector's Edition box specifically states this on the back of the box:

Collector's Exclusive: "Divine Aura"
 * Each character you create manifests the gods' favor with a glowing aura, visible to all.

What the Divine Aura does is creates a sparkle from the hands of a character, color and effect depending on the character's primary profession.
 * The Warrior's Aura is of Balthazar, a flamelike orange sparkle rising from the Warrior's hands.
 * The Ranger's Aura is of Melandru, ethereal green butterflies fluttering from the Ranger's hands.
 * The Monk's Aura is of Dwayna, hands pulsating in blue light with wisps of blue left in the Monk's hands path.
 * The Elementalist's Aura is also of Dwayna, mimicking the Monk's Aura.
 * The Mesmer's Aura is of Lyssa, a pure pink sparkle trailing the quick motions of the Mesmer's hands.
 * The Necromancer's Aura is of Grenth, a green drizzle of sparks destined for the Underworld.
 * The Assassin's Aura is of Lyssa, a pink shuriken glowing in the Assassin's hands.
 * The Ritualist's Aura is of Grenth, hands pulsating square with lightning symbol in aquamarine with wisps of turquise left in the Ritualist's hands.

The Divine Aura is attached to the Collector's Edition CD-key. It may NOT be transferred to other accounts and adding a collectors edition key to a normal account will not give you any additional slots, nor will you be given back your original key (so doing so will effectively mean that you lose the 4 slots normally associated with the key.)