Requires the library mod Collective.
Altered Damage is a minimalistic configurable mod that alters damage taken with a modifier by players and other entities. It's both possible to decrease and increase the damage. There is an extra config option which prevents taking fatal damage from the extra modifier, from sources such as poison and starvation.
Configurable: ( how do I configure? )
preventFatalModifiedDamage (default = true): When enabled, does not change the damage output if it would be fatal with the modifier and not fatal without. Prevents dying from for example poison and starvation.
alterEntityDamageTaken (default = true): Modifies the damage another entity receives
alterPlayerDamageTaken (default = true): Modifies the damage a player receives
entityDamageModifier (default = 2.0, min 0.01, max 20.0): The global damage modifier for other entities.
playerDamageModifier (default = 2.0, min 0.01, max 20.0): The global damage modifier for players.