Question regarding Aura cards with defensive value in a combat chain

[craggy quarry]

The specific example I saw was Vynsset player who was blocking an attack with an Aura (Malefic Incantations) from their hand and their Fyendal's tunic with 3 counters on it

The player activates the Tunic, activating their spellbound creepers to instant speed the Deadwood Dirge in hand. Destroying the Malefic blocking the attack, and creating the runechants.

Is this possible? If the aura would be previously in play and forced to block, I would believe it. But I'm not that sure when it is played from hand.

[silent tiger]

Short answer: yes, this is possible, but...

Long answer: first let's stipulate that Creepers is actually live, here, because in the exact scenario you described, it's not. The defending player here has yet to block with an attack action card, which is a requirement for activating Creepers on an opponent's turn.

Maybe they did so on an earlier chain link, and we're just wondering if Deadwood Dirge can "destroy an aura you control" if said aura is merely a defending card, not an aura in the arena.

The answer is yes, because Dirge doesn't say "... an aura permanent you control"

You control your defending cards while they're on the combat chain, and the Malefic card has the Aura subtype, and that's all Dirge cares about.

[craggy quarry]

Yes, I forgot to clarify that the creepers was live due to a previous block with an attack action card.

The answer is yes, because Dirge doesn't say "... an aura permanent you control" <- This is good to know

[naive egret]

I have a follow up question here, if you destroy a Sigil aura, that have effects upon leaving the arena, do those effects trigger? I ask because the combat chain is a part of the arena, right?

[oak ether]

no because its ability is not active while defending

[naive egret]

makes sense