You can only activate 1 "Last Hope of Nephthys" per turn
Phantom Knights all compliment each other, easily being able to dump themselves into the Graveyard to use their powerful effects that trigger from banishing themselves from the Graveyard
To be completely clear, if the card says "prowl cost was paid, X", you only get X if you paid the Prowl cost
With the ability to create a swarm of little nippers, then pump them up each time he attacks, Edgar naturally works best in a horde-style deck that can swiftly overwhelm opponents
We were expecting this situation to be repeated with MTG Marvel Super Heroes, and the multiple Marvel MTG sets which are more or less confirmed to be in the works, but it looks like someone altered the deal
It also has applications in bigger types like Dragons or Giants, where you can leverage power buffs or Double Strike to aim for devastating one-hit-kills