The mono-Black five-drop turns spell casts into a free surveil 1 and then on a 4/5 body, and then at the beginning of your end step you'll have each foe sac their dork like a free Edict unless they pay 2 life per spell in your graveyard...ouchie
Of note, the precon does not have Swiftfoot Boots or any other form of hexproof and haste on Auras or Equipment and this seems like a deliberate choice to prevent this exact scenario
With the right setup, this card can take players out of the game without entering combat even once
W is about 1.38, assuming 55% win rate in ranked draft
Theyre both copies of Remove Soul
A staple is having resources build up over time, replenishing each turn, like Magic: The Gatherings Lands, or Mana Gems in Hearthstone or Shadowverse