Monstrous Veil

Rhinar Specialization

Action - Destroy this: Draw a card then discard a random card. Go again

Battleworn

Rulings

From the Heavy Hitters release notes

If you cannot draw or discard cards (no cards in deck and/or no cards in hand), you can still activate this ability.
If you cannot draw a card, you must still discard a random card if possible.
There is no priority between drawing a card and discarding a card (i.e. you cannot play cards or activate abilities if you don’t have priority)

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.