You can Special Summon this card (from your hand) by discarding 1 card. You can only Special Summon «Nightmare Apprentice» once per turn this way. If this card battles a monster, neither can be destroyed by that battle. If this card is Normal or Special Summoned: You can add 1 Illusion monster from your Deck to your hand, except «Nightmare Apprentice». You can only use this effect of «Nightmare Apprentice» once per turn.