In Fantasy Grounds Unity, rerolling damage using the feats Savage Attacker and Piercer cannot be done with just effects.  The user must roll the damage and reroll what is needed, then the host must move the correct damage to the corresponding target.

This extension automates the use of these feats.

When damage is rolled, the extension will check if the Combatant has the Savage Attacker and/or Piercer feat.  It will then check if the attack is from a melee weapon for Savage Attacker and if the attack does piercing damage for Piercer. 

As the feats can only be used once per turn, it will also check if the combatant has used the feat this turn.  Because of this, the combat tracker needs to be used as intended as the feat use will reset when the Next Actor button is pressed.

The damage will be rolled, then a window will pop up asking if the user wants to use the corresponding feat.

If the user presses the Checkmark for Savage Attacker, then the damage from the weapon (not including extra damage from other effects, etc. per the feat) will be rerolled and the highest damage will be applied to the target(s).

If the user presses the Checkmark for Piercer, then the die corresponding to the damage dice that will benefit the most from a reroll will be rerolled and the correct damage will be applied to the target(s).