Fear is an aura with the fear value affecting the rate at which nearby squares are stuck. Friendly units are unaffected by the fear aura. Enemies hit by a fear effect will get a cumulative penalty to their morale, to a maximum penalty of -5. Being hit by a fear effect may cause the victim's squad to make a morale check next round, though at most one morale check may be triggered each round regardless of how many fear effects were suffered.

The morale debuff is halved every round, rounded towards 0.

Famously not even Illwinter knows the exact mechanics of how Fear works.

Fear acts identically to other auras when determining which squares are hit, and how frequently; however the lack of visual effect or logged messages makes seeing its effects significantly harder than other auras. The manual states that the value of fear affects the area of effect, but as with other auras, fear cannot reach further than one square from the origin until it reaches a value of 25 or higher.

Fear comes in two forms. Both versions apply the cumulative penalty to morale, but differ in their ability to force morale checks. The weaker version is used only by the Howling Bows wielded by Ancestor Vessels, and adds 1 to the "morale problems" value of an affect unit's squad, and the affected unit gains an additional +1 to its morale problems.

The common, potent version used by all other effects adds 1000 morale problems to all squad members, and then sets the morale problems of the affected unit to 1000.

A squad is guaranteed to take a morale check if any member has a morale problems value that is 10000 or higher. Lower values may cause checks but is subject to more requirements. Because the checks are done in sequence, it is impossible to force the morale problems value of a squad of nine units high enough with a single fear effect such as one cast of Panic.