All Fiend-Type monsters you control gain 500 ATK.
You can target 1 "Archfiend" monster you control; banish 1 other Fiend-Type monster you control, and if you do, Special Summon from your hand, Deck, or Graveyard, 1 "Archfiend" monster with same Level as the targeted monster.
You can only use this effect of "Archfiend Palabyrinth" once per turn.