Dervishes are sects of humans that have cultivated a fanatical devotion to a deity, and so, when going to war in that deity's name, are nearly unstoppable. Though they can be dangerous if angered, they are generally helpful, friendly, compassionate people, whose fury is reserved for those who threaten their society or their people.
A dervish's battle frenzy makes them completely fearless, and gives them a bonus to damage.
Large dervish groups are lead by skilled fighters and clerics of the gods of war, law, and the sun. Dervishes occasionally employ magic-users in their leadership as well.
Dervishes dress lightly, often using large swords and chainmail. They disdain ranged combat, preferring to charge into the thick of melee.
Dervish temples are heavily fortified affairs, and contain few noncombatants: most anyone in a dervish temple is a trained and fanatical fighter.