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While that card is exiled if you don't have a legendary Vampire in play, Olivia can be a great way to cheat massive high-impact threats into play if your deck has an easy way of putting them into the graveyard
Creature theft effects and bounce effects make it so that running a card as suboptimal as Fowl Play shouldnt be necessary even if it has an occasional nice interaction, like turning an Elesh Norn or Griselbrand into a Chicken where stealing/bouncing it may have caused you to lose
Wight of Precinct Six: This can get insanely big with a table full of opponents
Their subsequent English release (and Japanese reprint) in EX Power Keepers saw the demand for Vaporeon, Jolteon and Flareon decline