3 official rulings from Bandai, last ruled Mar 28, 2024. Straight answers to how this card actually resolves.

When digivolving into this card from my hand, I activate an effect on another card that reduces digivolution costs. What happens to this card’s digivolution cost?
The digivolution cost is equal to the number of cards in your security stack minus the amount reduced by the effect. If you have 4 security cards and activate an effect that reduces digivolution costs by 2, the final digivolution cost will be 2. (4 minus 2.)
Ruled Mar 28, 2024
This card’s reads “up to 4.” Can I activate the effect if I have 3 or fewer digivolution cards?
Yes, you can. This card's allows you to choose any number of digivolution cards to trash, from 1 to 4. If you have 3 or fewer digivolution cards, you can activate the effect as long as you can trash 1 or more of them.
Ruled Mar 28, 2024
I trash 2 digivolution cards to activate this card's . Can I have 2 of my opponent's Digimon both get -3000 DP?
No, this effect can only target 1 of your opponent's Digimon.
Ruled Mar 28, 2024
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Questions and answers are Bandai's official rulings, collected and translated by the DigimonCardGame Wiki community and reused here under CC BY-SA. Card names and card text are © their respective publishers; Combalo is not affiliated with Bandai.