By means of this spell, the caster ensorcels one person in such a fashion that the person truly enjoys killing and will immediately go berserk, attacking to kill friend and foe alike for the duration of the spell, unless a saving throw vs. spell is made. The definition of person is the same as for the first level wizard spell, charm person, and the same restrictions apply, save that the charmed character has no qualms about slaying others.
The charmed individual will not attack the caster of this spell unless the caster attacks or harms the charmed individual first. If this happens, the charmed individual will attack only the caster.
If there is no one for the charmed individual to attack, he acts normally. As soon as someone other than the caster comes within sight (within the duration of the spell, of course), the dire charm takes hold and the charmed individual rushes to the attack.
The berserk attacks of the charmed individual do not grant any additional powers or abilities. If given a choice between two different ways to attack, the charmed character always chooses the most deadly (he will cast a fireball spell before drawing his dagger, for instance). If the charmed character is forced to attack something much more powerful, the DM may permit a second saving throw vs. spell to break the charm.