Also... what is the purpose of the leader of the race card.. it has a lighter back than the rest. Is this for random selection of race by making them into a different race selection deck?
It's primary function is when you're customizing decks. The leader you choose determines which cards you can have in your deck at no moon cost (any card that's of the same people as the leader) and which cards have a moon cost to add (everything else). You're allowed 10 moons worth of "outside" cards in your deck when customizing (unless you're using inquisitors, which modify the deck customization rules).