Rulings
Q1: If this card's Your Turn effect triggers, can I choose to not activate it?
No, you can't. If the effect triggers, it must activate.
Q2: Can I choose different Digimon for the Digimon that gains Alliance and the Digimon that attacks for this card's Your Turn effect?
Yes, you can.
Q3: After my Digimon gains Alliance with this card's Your Turn effect, can I choose to not attack for the part of the effect after "then"?
Yes, you can.
Q4: My Tamer has 4 colors. If this card's On Play When Digivolving effect activates, do I perform De-Digivolve 2?
No. You perform De-Digivolve 1 twice, not De-Digivolve 2. When performing De-Digivolve 2, the top 2 cards are considered to be trashed at the same time, but when performing De-Digivolve 1 twice, the top 2 cards are trashed 1 at a time. For example, if using De-Digivolve 2 to simultaneously trash the top 2 cards of a suspended Digimon and the 2nd card trashed is [[BT15-047|BT15-047 Kabuterimon]], its effect won't activate. However, if performing De-Digivolve 1 twice and the Digimon becomes [[BT15-047|BT15-047 Kabuterimon]] after the 1st instance of De-Digivolve 1 trashes a card, it won't be affected by the 2nd instance of De-Digivolve 1 and won't be trashed.
Data Sources
Lv.5 MetalGreymon BT21-061 U Ultimate | Vaccine | Cyborg/ADVENTURE [Digivolve] Lv.4 w/[Greymon] in name or w/[ADVENTURE] trait: Cost 3 [On Play] [When Digivolving] To 1 of your opponent's Digimon, <De-Digivolve 1> for every 2 of your Tamers' colors. [Your Turn] [Once Per Turn] When your other Digimon are played or digivolve, if any of them have the [ADVENTURE] trait, 1 of your Digimon gains <Alliance> for the turn. Then, 1 of your Digimon may attack. --- Inherited: <Alliance> (When this Digimon attacks, by suspending 1 of your other Digimon, this Digimon gains <Security A. +1> and the suspended Digimon's DP for the attack.)
Lv.5 MetalGreymon BT21-061 U Ultimate | Vaccine | Cyborg/ADVENTURE [Digivolve] Lv.4 w/[Greymon] in name or w/[ADVENTURE] trait: Cost 3 [On Play] [When Digivolving] To 1 of your opponent's Digimon, <De-Digivolve 1> for every 2 of your Tamers' colors. [Your Turn] [Once Per Turn] When your other Digimon are played or digivolve, if any of them have the [ADVENTURE] trait, 1 of your Digimon gains <Alliance> for the turn. Then, 1 of your Digimon may attack. --- Inherited: <Alliance> (When this Digimon attacks, by suspending 1 of your other Digimon, this Digimon gains <Security A. +1> and the suspended Digimon's DP for the attack.)
Lv.5 MetalGreymon BT21-061 U
Ultimate | Vaccine | Cyborg/ADVENTURE
{{DigivolveFromArchetypeOrTrait|3|4|Greymon|ADVENTURE}}
[On Play] [When Digivolving] To 1 of your opponent's Digimon, <De-Digivolve 1> for every 2 of your Tamers' colors.
[Your Turn] {{OncePerTurn}} When your other Digimon are played or digivolve, if any of them have the [ADVENTURE] trait, 1 of your Digimon gains <Alliance> for the turn. Then, 1 of your Digimon may attack.
---
Inherited: <Alliance>.