Seth, the youngest of three brothers, witnessed his oldest brother murder the other. The horror and power of that sin washing over him triggered his awakening.
It isn't known exactly how old Seth is, but tales of a mischievous sorcerer who draws power from the sins of mortals go back as far as any currently living sorcerer can remember.
Recently, Seth traveled to the American West, where he has found a plentiful supply of sin. He has gleefully taken on the role of gunslinger. He loads his revolver with magical bullets forged from the sins he collects, and hunts down rival sorcerers.
As Seth, your Grimoire contains 7 sin cards, one for each of the 7 deadly sins. This new card type can be played for free. You spend an action to play a sin card, resolve its effect, and then perform a different action.
The effect of a sin card is minor, but after that effect, the sin card is attached to your character skill card. For an action, you can rain a hail of magical bullets down on your enemies, dealing collateral damage based on the number of sin cards you have collected.