Duelist Gauntlets

Attack Reaction -

, destroy this: Target sword attack gets "Reaction cards get -1

while defending this."

Battleworn

Rulings

From the Mastery Pack Warrior release notes

Duelist Gauntlet’s first ability is a targeted effect, which requires a sword attack in order to be activated. A previous sword attack where the sword is still on the chain link is a valid target.
When Duelist Gauntlet’s first ability resolves, all cards that were already defending the targeted attack (e.g. attack reactions added as defending in the defense step) as well as cards that have not yet resolved and become defending (e.g. defense reactions after they resolve on the stack) will be affected.
“Reaction cards” is any card with the Reaction type in its typebox. This includes attack and defense reactions. It does not affect cards that were added to the chain link by a defense reaction activated ability unless they also have the Reaction type. For example, Quickdodge Flexor becomes defending following the resolution of a Defense Reaction ability, but is not itself a card with a Reaction type.
This continuous effect will only apply to the targeted sword attack and reaction cards defending the targeted attack will get the -1. Subsequent attacks made by the same sword on the combat chain will not have this continuous effect applied to them as they are different sword attacks.

Keyword notes

Battleworn - Equipment that wear down after each time they are used to defend. If you defend with a card with Battleworn, put a -1{d} counter on it when the combat chain closes.

When you defend with a card it remains on the combat chain until the chain closes, therefore you cannot defend with an equipment multiple times on the same combat chain.
A -1 counter stays on the card until the card is destroyed or the game ends.
If the defense of a card that is defending is below zero, its defense value is considered to be zero.
When this card is destroyed, it is sent to your graveyard. (Not when it has 0)
When this card is destroyed, it is sent to your graveyard.
If the defense of a card that is defending is below zero, calculate as if its defense is zero.

All keywords

ClassWarrior

TypeEquipment

SubtypesArms

Defense1

KeywordsBattleworn

SetsMPW