What exactly is "rhetorical effect?

What does Ceruli, Guru of Dark World's effect mean?

• 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. ok, so my understanding of its effect is this. you use a card to discard it, so it is summoned to your opponent's field, well since it is a "Dark World" card its effect should activate: Your opponent must discard 1 card. well since it is on YOUR OPPONENT'S side it is their effect meaning it's THEIR OPPONENT who discards......is that right? if my assumption isn't correct then this card is not very useful

• Answer:

  hmm it's pretty simple yea and i guess u understand correctly as well the 1 who actually discards by ceruli's eff is the <original owner> of ceruli. Basically it's purpose is to have u discard a dark world card of ur choice, to get the eff that would activate if it was discarded by an opponent's card effect(since ceruli is now under your opponents control). eg if i'm not mistaken, if ceruli is specialed to ur opponent's side and u disc grapha for his eff, u would not only destroy something but revive 1 as well(grapha's other obscure eff if i remember correctly) well, that being said, u r right ceruli is NOT a good card, and should not b used in full-competitive dark world decks 4 many reasons;) it has some uses in slower and weaker dark world decks tho;)cheers