Damage cap is a mechanism of how damage dealt against certain monsters in a single hitsplat is limited. Monsters found with a damage cap are quite rare, and most of them are high level bosses, but there are exceptions. The capping effect is calculated after all other damage modifiers. Damage caps are usually most easily seen with Ruby bolts (e), as their random special effect, when activated always reduces the target's current life points by 20%. For abilities that hit multiple times, such as Deadshot, the damage cap is applied separately to all the hits, making them more effective in bypassing the cap than abilities that does one high hit, such as Meteor Strike, although the damage capacity still depend largely on the situation.
Damage caps prevent effects that deal damage equal to a percentage of the target's life points, such as ruby bolts (e), from dealing extremely high amounts of damage to monsters with a large number of life points. Damage caps may also be negated or become passive depending on other mechanics, such as the distance between the player; e.g. while fighting Legiones.
For abilities whose damage is based on the enemy's maximum life points the cap applies to the total damage dealt. Most damage from abilities is capped at 10,000 damage (or 12,000 for critical hits). Tuska's Wrath is capped at 15,000. The cap for ultimate abilities, if any, is unknown but at least 20,000. Mazcab abilities are capped at 30,000 damage.
The following monsters are known to have permanent damage caps:
- Vampyre Juvenile
- Fumus, Umbra, Cruor and Glacies, 2,000
- Kal'Ger the Warmonger, 5,000
- Apep and Heru, 50 (during the quest; no cap inside the Dominion Tower)
- Prehistoric abyssal, 1
The following monsters are known to have temporary or dynamic damage caps:
- Enduring glacyte, damage cap based on its distance from parent glacor
- Giant Mole, when moles are summoned to her aid
- Lava strykewyrm
- Luminescent icefiend, cannot deal damage past certain intervals
- Legiones, cannot deal damage past certain intervals
- Sagittare, cannot deal damage past certain intervals
- Shadow nihil, damage cap based on distance
- Warped Gulega, damage reduced for players
- Nex, during her Zaros phase
- World-gorger Shukarhazh, depending on which eyes have and have not been engorged, as well as the combat style used by the player.
- Mega Duck, which takes less and less damage as its health depletes, and all damage is capped at 1 when it is under 1000 life points.