Decay

Decay is a status effect which instantly disables a number of traitss of the affected unit, either until the battle ends or those traits are later Restored. The number of traits disabled is equal to the intensity of the effect. Which traits are disabled is chosen by the inflicting unit.

In general, if an item listed under a character's traits has a number, it is a trait that can be disabled by Decay. Usually, that number also indicates how many traits the item counts for. For example, "+5 Magical offense" is five traits for the purpose of Decay - each of these five traits is "+1 Magical offense."

For an official list of traits that may be disabled by Decay, see List of traits. Traits marked as "Decayable" can be disabled by Decay.

What it Represents
Decay is a fairly versatile mechanic that can be used to represent any number of things that might start to compromise the innate resistance of foes. For example, it might represent a unique acid that renders particular equipment useless, or it might be a mind reading that detects and compensates for an opponent's strengths.