Can I stack Reaper's Row and Ezreal dashing triggers on defense to resolve Ezreal's first and then resolve Reaper's Row?
No, you cannot stack the triggers to resolve Ezreal's ability before Reaver's Row.
In Riftbound, the order in which triggered abilities are placed on the chain is strictly defined by the game rules, and they resolve in Last-In, First-Out (LIFO) order. Because Reaver's Row is a "When you defend" trigger belonging to the defender, it is placed on the chain after the attacker's "When I attack" triggers. Consequently, Reaver's Row will always resolve before the attacker's abilities.
Here is the correct sequence of events:
- Combat begins: Ezreal, Dashing (as the attacker) and the defender's unit (at Reaver's Row) gain their combat designations.
- Triggers are placed on the chain:
- The Attacker's "When I attack" triggers are placed on the chain first.
- The Defender's "When you defend" triggers (including Reaver's Row) are placed on the chain second, on top of the attacker's triggers.
- Resolution (LIFO):
- The chain resolves from the top down. Reaver's Row resolves first.
- When Reaver's Row resolves, you make the choice of whether to move the unit to the base. If you choose to move it, the unit leaves the battlefield.
- Ezreal's ability then attempts to resolve. Because Ezreal's ability requires the target to be at the battlefield ("here") to execute its effect, and the target is no longer present, the ability fails to resolve (it "whiffs").
Regarding your note on targeting: While it is true that targets are locked when an ability is placed on the chain, the ability must still be able to execute its instructions upon resolution. If an instruction specifies that an effect must occur "at a battlefield" or "here," and the target is no longer at that location, the instruction cannot be carried out. This is a standard interaction in Riftbound where moving a unit out of the combat zone effectively causes targeted combat abilities to fail.