While this card is in your hand or Graveyard, if a face-up Nekroz or Zefra card(s), except Zefraxa, Flame Beast of the Nekroz , is destroyed by battle or card effect while in your Monster Zone or Pendulum Zone: You can Special Summon this card. You can only use this effect of Zefraxa, Flame Beast of the Nekroz once per turn.