Duelingbook Forum

If I have a monster that can prevent their destruction, like Gouki The Great Ogre, replacing the monster that will be destroyed with other that is already inmune to it, like Gouki The Giant Ogre (Being indestructible by battle and inmune to monsters effects with less than the ATK the monster has.), will their inmunity prevail or will they be destroyed, regardless of their own protection?

If it can't be destroyed then you can't apply any effect that would replace it being destroyed, because it wouldn't be destroyed

You cannot apply an effect that would not do anything. You cannot banish the card if the monster you are trying to protect already cannot be destroyed.