Some mages don't want to dirty their own hands in battle, so they use this spell. Casting it forces the weaker minded enemy under the caster's control, allowing them to use their new puppet to attack other foes. This spell only works on one creature, and stronger willed foes will be able to resist it completely. Thus, use it with caution.
The more powerful variant of this spell is Mass Charm, which will lead to an entire group of foes battling each other.
A most effective tactic to use against enemies is to charm members of their party to work against them. However, this spell is most difficult to apply where it could be of the most help, against the most diabolical of foes, those of superior intelligence. Control of a charmed individual is limited to fighting and moving; it does not extend to use of magic or special forms of attack. This spell can also be used to bring back party members after they have been charmed by a foe.
An Xen Ex requires a careful mixture of nightshade, to poison the mind; a black pearl, for projection; and spider silk to bind loyalty.