There are creatures so large and horrifying, or supernatural horrors so unholy and terrible, that their mere appearance on the battlefield can cause the bravest and most steadfast of veterans to turn tail and flee.
Models that cause Terror also cause Fear. In addition, the following rules apply. Fear-causing models or models with Immunity (Fear) treat Terror-causing monsters as causing Fear, rather than Terror – this is an exception to the rule that makes Fear-causing creatures immune to Fear. Terror-causing models have the Immunity (Fear/Terror) special rule.
Run for Your Lives!
If a Terror-causing creature declares a charge, the target unit must immediately take a Panic test. If the test is passed, all is well and the unit can declare charge reactions normally. If the test is failed, the unit must make a Flee! charge reaction. Note that, if the target unit is not allowed to take any charge reaction (if, for example, the Terror-causing unit charged as a result of a pursuit or a random move), then the target does not take this test.
If a unit wishes to declare a charge against an enemy that causes Terror, it must take a Psychology test to overcome its terror first. If the test is failed, it may not declare the charge against the Terror-causing unit, but may choose to declare a charge against another unit following the rules for Redirecting a Charge. If the Psychology test is passed, the unit may declare the charge as normal.