If something else becomes a copy of The Soul Stone, it must be harnessed separately
Essentially, it lets you destroy creatures or artifacts, and then their owner gets to play the same number of random artifacts or creatures from their library
The Nazgul is a special card, letting you play with up to nine copies of it in your deck, and as a special treat, there are nine different artworks for Nazgul, each one depicting a different human king who fell to the temptations of Sauron
Edgar must be under your control in order to start casting an artifact spell using its first ability, but it doesn't need to stay under your control throughout that process or be under your control as the spell resolves
Its good when youre behind, its good when youre ahead, its good when youre at parity and its good in the developing stages of the game