If this card is Normal or Special Summoned: You can send 1 Fiend or Zombie Ritual Monster from your hand or Deck to the GY, then you can add 1 Ritual Spell from your Deck to your hand. If this card is banished: You can target 1 of your banished Level 4 or lower Fiend or Zombie monsters; Special Summon it. You can only use each effect of "Dark Necromancer" once per turn.