Soul Abilities are a group of Dark Eldar exclusive abilities that use the Soul resource to activate. Using them gives the potential to damage morale and even the health of enemy units. There are 6 of them, and can be used at any time during the battle, but must be given time to restore, just like any regular unit ability.
They are very useful for turning the tide of a battle; they grant such powers as detection and instant ability restoration, allowing for greater damage to the enemy. As well as these abilities, some can severely damage morale and unit health, and weaken armour. Some abilities have side effects, such as being able to damage the player's units as well as enemy units. Regardless they are a great asset and are used very commonly in battle.