So long as you can keep it alive and get it to the attack phase, It That Betrays can win games all on its own
Its beauty and relative rarity are the only real reasons to cherish it, though
Duplicates of ex cards are common in sets
And since the Hero deck is faster out of the gates and presumably can inflict some significant damage before the Rats are much use on defense, if the Plague Rat deck does eventually shift to offense, must it hold some of its forces back, and if so, how much
Speaking of vocabulary, we changed 'in play' to 'the battlefield,' 'remove from the game' to 'exile,' and enchantments that enchant things to 'Auras.' Also, we eventually shifted things around so that every card type is simply listed