If you remove "Nyarlathotep, the Crimson Radiance" from your hand as this card enters the field, it will continue to gain Imperishable and "When this card deals..." if it's destroyed and put into a ruler area. If this card is destroyed while it has Imperishable and you later play its judgment process again, it will continue to have the gained abilities, even if you don't remove another copy of Nyarlathotep.