Maze of Muertos

"Zombie World" in the Field Zone cannot be destroyed by card effects, also neither player can target it with card effects. (Quick Effect): You can banish this card from your field or GY; activate 1 "Zombie World" from your hand or Deck. You can only use this effect of "Necroworld Banshee" once per turn.

Necroworld Banshee

Ancient Guardians

Cannot be Synchro Summoned. Must be Special Summoned (from your Extra Deck) by sending 2 monsters you control with a Level difference of 1 to the GY (1 Tuner and 1 non-Tuner). If this card is Special Summoned: You can activate 1 "Ursarctic Big Dipper" directly from your Deck. You can Tribute 1 Level 7 or higher monster; add to your hand, or Special Summon, 1 "Ursarctic" monster from your GY. You can only use each effect of "Ursarctic Polari" once per turn.