A critical unit hits my vanguard, 2 cards are put into my damage zone, and this card is the first card. Can I call this card?
As a crtical 2 unit hits your vanguard, 2 cards are put from the top of your deck into your damage zone one at a time. Because of that, if the first card that is put into the damage zone is this card, you may call it, but you may not call it if it is the second card put into the damage zone.
After this ability is triggered, this card is put face down by the cost of another ability before this ability resolves. During the resolution of the effect of this card, can I call this card?
Yes, you can. Even though this card face down i nthe damage zone does not hold any information such as power, clan, nor text on the front side, as this is a change of state from face up to face down and not moved to the drop zone or other zones, it is still treated as the same card.
When this card is face down in the damage zone, when other cards are put to the damage zone, does the ability trigger?
No, it does not. Cards that are face down in the damage zone do not hold any information such as power, clan, nor text on the front side. Thus, the ability will not trigger.
This unit is called into the same rear-guard circle of a unit that is being attacked, and the unit that is being attacked is put to the drop zone. What happens to the battle?
The battle will proceed as normal, followed by drive check and calling guardians. However, as this card is not an attacked unit, no power comparison will occur during damage step, is not hit, and no units are retired in battle.
When this unit and another of my 《Angel Feather》 are put to damage zone as the cost for the Limit Break ability of "Crimson Impact, Metatron", and I did not choose this card to call for the effect of the Limit Break. Can I still call this card using this card's ability?
Yes, you can.
For units with "When this unit", can I pay the cost twice to activate the ability twice when the condition is met?
No, you cannot. [AUTO] abilities can only be activated once when the conditions are met(e.g. "When this unit～"). Cost can only be paid once as well.
For the costs with "[Counter-Blast 2]-○○", what does "○○" mean?
The cards required as a condition to pay the cost. You can only pay the cost by fulfilling this condition. For example, when "[Counter-Blast 2]-<>" is stated, you cannot use a "Dragonic Overlord" in your damage zone as payment. Please put 2 face up <> cards face down instead.