It converts a percentage of damage dealt to a player back as health. However, the damage inflicted must be the same type as the eater for the property to function. The percentage of the damage converted to health stacks with other eaters of the same type, but is capped at 30%.
Eaters are charged over time provided you don't get damaged during that time. Damage Eater properties have a capacity to store up to 20 healing charges and convert charges every three seconds from the last time damage was received before they stop converting damage.
Some special attacks like Bleed are considered direct damage and only triggered with all type damage eater and not kinetic eater.
The amount of damage eaten is the sum of a specific eater taken as a percentage of the damage dealt. For example, if you have 30% Fire Eater and take 40 points of damage from a Flamestrike, then you may get back after a short while 30% of 40 thus 12 hit points.
The all type damage eater does not stack with specific eaters (if you have Damage Eater 10% and Fire Eater 20%, and take 20 fire damage, your eater will restore 4 health, the higher amount). All type damage eater is capped at 18%.