- You cannot use Eccentric Boy as a Tuner to Summon this monster because the other material monster must be 1 monster in your hand, and this requires 2 non-Tuner monsters.
- Your opponent only needs to have a face-up LIGHT monster when you activate this effect, not when it resolves.
- The effect to send LIGHT monsters to the Graveyard and inflict damage counts LIGHT monsters sent from your opponent’s hand to your Graveyard.
- The text, "If your opponent controls a face-up LIGHT monster, you can select and activate 1 of the following effects once per turn:" of "Ally of Justice Decisive Armor" is not treated as an effect.
- The effect of "Ally of Justice Decisive Armor" which destroys one Set card your opponent controls targets.
- Discarding your entire hand is a cost to activate the effect of "Ally of Justice Decisive Armor" which discards from your opponent's hand and inflicts damage.
- If one of the monsters sent to the Graveyard by the effect of your "Ally of Justice Decisive Armor" was sent to your Graveyard because it was owned by you and added to your opponent's hand by "Exchange", then the sent monster will be included in the damage inflicted.
- If an effect is chained to the effect of "Ally of Justice Decisive Armor" so that your opponent controls no LIGHT monsters when resolving the effect of "Ally of Justice Decisive Armor", then the effect of "Ally of Justice Decisive Armor" will still resolve properly.
- If "Eccentric Boy" is used as a Synchro Material Monster, then the other Synchro Material Monsters must be one monster from the hand. Thus, you cannot Synchro Summon a monster like "Mist Wurm" or "Ally of Justice Decisive Armor" which require two or more non-Tuner monsters.
- Konami Gameplay FAQ: Hidden Arsenal 3 -- Card Rulings (version 1.0)
- Konami FAQ: Synchro Monster > Ally of Justice Decisive Armor
- Konami FAQ: If the effect of "Ally of Justice Decisive Armor" send a LIGHT monster from the opponent's hand to your Graveyard, then will damage be inflicted?
- Konami FAQ: If there are no longer any LIGHT monsters on your opponent's field when resolving the effect of "Ally of Justice Decisive Armor", then is the effect applied?
- Konami FAQ: Can "Mist Wurm" be Synchro Summoned by using "Eccentric Boy"?
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