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

I use this card on one of my opponent's Digimon with a play cost of 5 or more, and <De Digivolve 1> causes it to become a Digimon with a play cost of 4. Can I use this card's effect to delete that Digimon?
Yes, if <De Digivolve 1> causes it to become a Digimon with a play cost of 4 or less, you can delete it.
Ruled Mar 28, 2024
Can I use this card to delete an opponent's Digimon with a play cost of 4 or less that doesn't have any digivolution cards, or on an opponent's level 3 Digimon?
Yes, you can.
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.