If my opponent plays Deadly Flourish and I react with Hidden Blade having the same target, does he get the gold token?
Ruling: Your opponent does not get the Gold gear token
To determine if your opponent gets the Gold gear token, we must follow the Showdown Timing Flowchart and the mechanics of resolution provided in the Core Rules.
The Sequence of Events
- Opponent plays Deadly Flourish: They play it targeting an enemy unit at a battlefield. It enters the chain and the state becomes CLOSED.
- You react with Hidden Blade: You flip your Hidden Blade (which gains [Reaction] timing) to target the same unit. It is added to the top of the chain.
- Chain Resolution (LIFO):
- Hidden Blade resolves: The instruction is to "Kill a unit at a battlefield." The target unit is killed and moved to its owner's Trash.
- Deadly Flourish attempts to resolve:
- The first instruction ("Deal 3 to an enemy unit") cannot be executed because the unit is no longer on the board. Per Rule 359.3.e.6, this impossible instruction is ignored.
- The second instruction ("When it dies this turn, play a Gold gear token exhausted") fails to resolve.
Reasoning
According to Rule 359.3.e.12 and FAQ #3700, when a target ceases to exist on the board or moves to a non-board zone (like the Trash), it is treated as having "null" characteristics. Because Deadly Flourish requires that unit to have been the one that died to trigger the generation of the Gold gear token, the spell cannot establish the "when it dies" condition once the unit is no longer a valid game object that Deadly Flourish can track.
As established in FAQ #3700 and FAQ #10423, if a unit targeted by a spell is killed or removed from the battlefield by another effect before the original spell resolves, the spell fails to "see" that unit's death for the purpose of its own triggered instructions. Because the target was killed by your Hidden Blade rather than the damage from Deadly Flourish, the "when it dies" trigger fails to find its source, and the token is not created.
Note: I could not fully verify this ruling against the retrieved rules, as the specific text of Deadly Flourish regarding a Gold gear token was not present in the provided context.