Overkill is a mechanic used only within the Yggdra Union series of games. Overkill is a more devastating variant to Fatal Damage and occurs when a target is hit with an overwhelming skill. Such conditions include having an elemental weakness to the skill, in addition to negative terrain effects and/or the equipment of the user boosting the power of the skill further. An overkill adds additional Bonus damage when Morale damage is calculated.
Judgment Zero has a small chance of scoring an Overkill without actually meeting the aforementioned criteria.