Because sometimes even heroes need a little help.

Karma cards grant temporary in-game bonuses to your players. They represent the Gods intervening on the player’s behalf as repayment (or prepayment) for what they deem to be “good deeds.”

Players "cash in" their karma cards by handing them over to the Gamemaster to gain the indicated bonus.

The cards can be handed out by the Gamemaster as awards for good role-playing, as bonuses for winning a particularly difficult battle, or even just because it's the player's birthday. However you decide to use them is ultimately up to you.