When it leaves the battlefield, you choose an opponent with more lands than you
If there are additional costs to cast a spell, or if the cost to cast a spell is increased by an effect (such as the one created by Thalia, Guardian of Thraben's ability), apply those increases before applying cost reductions
Special Summon 1 Level 4 or lower Fiend monster from your Deck in Defense Position, except "Ariane the Labrynth Servant"
One doesnt play a card like this just for the ability
[4] Addendum 8/12/24: I didn't notice at the time, but there is actually a simpler method when there is only one basic in the deck
Fiend Skull Dragon X WIND Level 5 [ Dragon / FusionEffect ] ATK 2000 DEF 1200 "Cave Dragon" + "Lesser Fiend" (This card is always treated as an "Archfiend" card.) A Fusion Summon of this card can only be done with the above Fusion Material Monsters