You can only control 1 "Nefarious Archfiend Eater of Nefariousness". If you control a Spellcaster-Type monster, you can Special Summon this card (from your hand). Once per turn, during your opponent's End Phase, if this card is in your Graveyard: You can target 1 face-up monster you control; destroy it, and if you do, Special Summon this card.
Requires you to control a Spellcaster to Special Summon from the hand.
Requires you to destroy one of your monsters to revive.
The low-level Nephthys monsters are all Spellcasters, letting you take advantage of Nefarious Archfiend’s Special Summoning. Their effects are also triggered when destroyed by card effect, letting you take advantage of Nefarious Archfiend’s revival cost.
You can summon Hand of Nephthys and Special Summon Nefarious Archfiend. Tribute both monsters to Special Summon Sacred Phoenix of Nephthys. On your opponent’s End Phase, destroy Sacred Phoenix to revive Nefarious Archfiend. Then, on your coming Standby Phase, Sacred Phoenix revives itself to wipe your opponent’s backrow.
Use both monsters in a Spellcaster deck to take advantage of their Special Summoning. Destroy Inari Fire when reviving Nefarious Archfiend to make use of Inari Fire’s self revival. This can swarm your field with monsters to use as tribute fodder or Synchro material.
Scrap Factory can make Nefarious Archfiend worth running in a Scrap deck. Destroy Scrap monsters when you revive Nefarious Archfiend, you won’t be triggering any of the Scarp monsters’ effects but with Scrap Factory on board you will get to Special Summon a Scarp monster from the deck. You can Special Summon Scrap Beast and pair it with Nefarious Archfiend to make Scrap Dragon.
Special Summons itself from your hand / Special Summons itself from your Graveyard
Could have been okay in Archfiends if not for its beast typing. Would tie up some loose ends for sure. (Discard with effects like a call of the archfiend/ trance archfiend to use cavalry's effects later, then when you do, use palabyrinth to summon another boss monster removing the 1500atk monster.)