Although the pop-up text shows "Crushing Hit" when it happens during combat, the in-game help describes Crushing Hits as "Fatal Blow" -

"Fatal Blow - Attacks with a fatal blow with a fixed chance if you don't get a critical hit when attacking with an advantageous attribute. The fatal blow inflicts 30% additional damage."

There are four types of hits that can occur:

  • Glancing Hit: 30% less damage
  • Normal Hit: 0% additional damage
  • Crushing Hit: 30% additional damage
  • Critical Hit: starts at 50% additional damage and goes up according to your Critical Damage value

See also: Hit Table

The most common situation when Crushing Hit might occur is when attacking with attribute advantage. This will give the attacker a small chance to Crush; but it still won't happen if one gets a glancing hit or a critical hit instead (This is most famously the case with Ifrit (Water) - Theomars. While his passive grants him attribute advantage whenever he attacks, he won't get a Crushing Hit if he gets a critical hit instead).

However, several monsters have a skill that guarantees a Crushing Hit. The following are the monsters with fixed Crushing Hit chances:

Arguably, the primary benefit of a guaranteed Crushing Hit is the prevention of a Glancing Hit, because the latter cannot apply debuffs.