Ceruli, Guru of Dark World

[ Fiend / Effect ] If this card is discarded to the Graveyard by a card effect: Special Summon this card from the Graveyard to your opponent's side of the field in face-up Defense Position. When this card is Special Summoned by the effect of a "Dark World" card: Your opponent must discard 1 card. ATK/ 100 DEF/ 300