All "Nephthys" monsters you control gain 300 ATK.
If this face-up card in the Spell & Trap Zone is destroyed by card effect and sent to the GY: You can Special Summon 1 "Nephthys" monster from your hand, Deck, or GY, but destroy it during the End Phase.
You can only use this effect of "Awakening of Nephthys" once per turn.