Sliver decks are based around each card granting incremental bonuses or individual keywords until you have an army of creatures with haste, +1/+1, vigilance, poisonous, trample, reach, and more
Fortunately, Karakas can help protect Phelia, and Ephemerate can serve as an alternate way to cheat your five-drops into play
Great design and easy to use
As Jay Annelli writes in the new book Planes of the Multiverse: A Visual History, Innistrad is home to all manner of monsters and fiends [where] Werewolves rage in the night, hunting beasts and humans with equal vigor. Standing against them (and the vampires, and the zombies, and the other hungry fiends) are the planes equally powerful human warriors
This changed the baseline of paying two life for a card into paying only one, which has been the norm lately, although there are expections and you generally end up paying more in other ways