Glidewell Fins

Action -

, destroy this: Put an arrow from your hand face-up into your arsenal. It gets +1

this turn. Go again

Battleworn

Rulings

From the High Seas release notes · June 6 2025

You may activate Glidewell Fins’ activated ability even if you do not have an arrow in your hand. You will still get the action point from go again.

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.