Nullify damage is an equipment attribute that occurs only in shields. Basically, this attribute grants you the ability to have chances of nullifying any damage, such as those from physical attacks, magic spells, starving, or even hanging.
This attribute of Nullify damage uses a multi-step formula: first it collects and calculates a sum of all these values (they can be added), and further use this sum value to get the final chance of nullifying damage.
In Elona version 1.22, it is possible to get a 100% chance of nullifying damage.
An example: You can wear 13 shields at the same time, each of them with the #####+ "nullify damage" attribute. Not even gods or the bottomless Void can threaten you.
Elona+[]
In Elona+ 1.37 and after, Nullify Damage no longer blocks all damage, it reduces damage taken by an upper limit of 50%.