Awaken your latent power of [Void] Void Light by earning experience, generating Orbs of Power, and defeating combatants to earn points; using [Void] damage grants substantially more points.
Energy weapons deal elemental damage. Void element weapons can be identified by selecting it in your character screen and looking for the [Void] symbol.
"Not everyone has the strength to stare into the Void and return to the surface with the power it offers." —Toland, the Shattered