How does targeting work in the Yu-Gi-Oh Trading Card Game?
That means those card effects won’t work if the targeted monster is gone. For example, if you activate “Soul Taker” on a Fusion Monster, and your opponent activates “De-Fusion”, the targeted monster is gone so the effect would not activate. If your opponent activates “Book of Moon” to flip their monster face-down when you activated “Sakaretsu Armor”, the card’s target is technically not there.