Obsidian Fire Vein

Whether you’ve played a Draconic card this chain link is constantly checked while Obsidian Fire Vein is an attacking card on the chain link. Draconic cards played on other chain links where Obsidian Fire Vein was an attacking card will not satisfy the condition for the current chain link. The conditional effect will only look at the current chain link.

If you haven’t played any Draconic cards this chain link, then play a Draconic card (e.g. instant) before damage is dealt, this will have +1 during damage calculation.

You don’t retroactively deal extra damage if you’ve passed the Damage step (i.e. damage calculation) without playing a Draconic card, and then proceed to play a Draconic card.

Go again is checked during the Link step. If you haven’t played any Draconic cards this chain link, then play a Draconic card (e.g. instant) before the attack’s Link step (i.e. after damage is dealt, but before playing another attack), you will gain an action point from go again during the Link step.

You don’t retroactively get an action point from go again if you’ve passed the Resolution step without playing a Draconic card, and then proceed to play a Draconic card. (e.g. after you’ve played another attack, closed the combat chain etc.)