Can I counter a unit when played ability?
No, you cannot counter a "When you play me" ability (or any unit ability) using cards that counter spells.
According to RiftJudge FAQ #1137 and RiftJudge FAQ #2214, counter cards like Defy or Wind Wall specifically target spells. Since unit abilities are not spells, they cannot be countered by these effects. There is currently no "ability counter" card in Riftbound.
Key Rules and Nuances:
- Unit Abilities create a chain: While you cannot counter these abilities, they do use the chain (as per RiftJudge FAQ #2214 and Rule 383.3).
- Reaction Window: Because the ability uses the chain, you can add [Reaction] cards to that chain in response to the ability, provided you have a valid target or interaction. You cannot, however, use [Action] cards unless you have priority and the chain is empty (per RiftJudge FAQ #3425).
- Negation vs. Countering: While you cannot counter the ability, some cards might allow you to negate its effect (e.g., preventing damage or changing a target), but this is distinct from countering the ability itself.
Summary of the process:
- Playing the Unit: When a unit is played, it enters the battlefield and its "When you play me" ability triggers and goes on the chain. You cannot react to the unit being played itself (RiftJudge FAQ #9749, #11175).
- Responding to the Ability: Once the ability is on the chain, you may play [Reaction] spells.
- Countering: If you attempt to use a "Counter a spell" effect, it will fail because the ability is not a spell.