Yes, I keep mentioning the Thumb because it's that important
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
In return, you are able to create a Hero Token which acts as a creature with 1 Power and 1 Life, but you are able to put as many counters on it for each life you paid which increases both by 1 per counter
What is interesting is that glorious art, courtesy of Zina Saunders
The first sets that contained serialized cards make up the bulk of this, with up to 65 cards getting 1 in 500 serialized versions