This mod make villagers absolutly immune of any type of damage.
This would help to users that have zombies near or other mods that can kill for accident the villagers of your world.
Is very usefull for villagers whit especific trade items or for farms (Iron,Villagers,etc)
If you know a bit of programation, the mod is very simple, it only detect when a villager is attacked and it cancels the atack so villager does not get knockback or recive damage/get killed.