Exorcism

Exorcism is a Retribution paladin ability, available at level 46.

Improvements

 * Sanctity of Battle
 * Holy Avenger

Equipment sets

 * Valorous Aegis Battlegear (level 80) - 2/5 increases the damage done by your Exorcism and Hammer of Wrath abilities by 10%.

Background
This spell was one of the Paladin's abilities in Warcraft II: Tides of Darkness:

Calling upon the forces of light and purity, the Paladin is able to dispel the walking dead that plague the lands of Azeroth. Exorcism can be used to cause injury to entire groups of these undead terrors, or to utterly eradicate a lone creature. These creatures of Hades seem to gain strength in numbers, thus the greater number of undead that are exorcised within a group, the less actual damage each undead will take. This act is extremely taxing upon the Paladin, making it necessary for him to observe a period of rest before once again invoking this great power.

Tips and tricks

 * Amount of damage dealt by Exorcism is increased by 15% of your attack power and 15% of your Spell power.
 * Exorcism is one of the few ranged attacks available to Paladins.