EntityLivingDamage Event is fired just before damage is applied to entity. At this point armor, potion and absorption modifiers have already been applied to damage - this is FINAL value. Also note that appropriate resources (like armor durability and absorption extra hearths) have already been consumed.

If this event is canceled, the Entity is not hurt. Used resources WILL NOT be restored.

You will need to cast the event in the function header as this class:
crafttweaker.event.EntityLivingDamageEvent
You can, of course, also import the class before and use that name then.

EntityLivingDamageEvent implements the following interfaces and are able to call all of their methods/getters/setters as well:

• ILivingEvent
• IEventCancelable

ZenGetter	ZenSetter	Type
ZenGetter damageSource	ZenSetter ​	Type IDamageSource
ZenGetter amount	ZenSetter amount	Type float