Would I be able to KO Ronin to prevent the damage from the unblocked character die?
Yes.
When would that KO occur?
Ronin may be KO’d in the Use Action Dice and Global Abilities sub-step of the Attack Step. Refer to the following ruling on Black Swan (point 4):
https://win.wizkids.com/bb/viewtopic.ph ... 52fbc5b181When damage is assigned or preemptively?
In this scenario, Ronin’s ability is preemptively resolved before the combat damage is assigned.
If it is when damage is assigned, can Ronin still deal their A back to the blocked die first?
This question is not applicable based on the above answers.
Further explanation.
In review, the Attack Step has six sub-steps:
1. Declare Attackers
2. Declare Blockers
3. Use Action Dice and Global abilities
4. Assign Combat Damage
5. Apply “when damaged” abilities
6. Resolve Damage and “when KO’d” abilities
For the scenario provided above, in order to prevent the application of combat damage by the unblocked attacker, Ronin would have to be KO’d in the Use Action Dice and Global Abilities (sub-step 3 of the Attack Step) as established in the cited Black Swan ruling. Therefore, Ronin would not be active when combat damage is assigned in sub-step 4 of the Attack Step. Ronin would neither deal nor receive combat damage, but has been declared as a blocker and would stop any non-Overcrush damage from the attacker he was assigned to block. Refer to the following rules:
Rule 2.7.1.8 An attacker that is KO’d by ability damage before the Assign Combat Damage sub-step will not deal its combat damage.
Rule 2.7.2.4 Once an attacker is blocked, it is considered blocked until the end of the Attack step, even if its blocker is subsequently removed from the Attack Zone (i.e. once blocked, always blocked).
Rule 2.7.4.3.2 If the attacker is blocked, but the blocker was subsequently removed by an ability, the attacker is still considered to be blocked and will not deal combat damage to the Inactive player (once blocked, always blocked). Likewise, a removed blocker will not assign its Attack value in damage to the attacker. An exception is the application of Overcrush damage.
The result of this scenario at the end of turn is:
- - Ronin goes to its Prep Area (because he was KO’d)
- - the attacker Ronin blocked does no damage and returns to its Field Zone
- - the unblocked attacker does no damage and is moved to its Used Pile
In addition, because, unlike Black Swan, Ronin prevents all damage (i.e. both ability and combat damage) from one source, he could be KO’d in the Use Action Dice and Global Abilities portion of the Main Step. In this situation Ronin acts as an
interrupting ability, meaning that the controlling player can pay the cost (the KO of Ronin) when the ability damage is initiated to prevent the ability damage before it is resolved. Refer to the following rule:
Rule 3.2.8 Only abilities that would prevent, reduce, or redirect an ability can interrupt the queue. An interrupting ability happens simultaneously, potentially preventing other abilities in the queue from initiating.